1 /*
2  * copyright (c) 2001 Fabrice Bellard
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 //#ifndef AVFORMAT_AVFORMAT_H
22 //#define AVFORMAT_AVFORMAT_H
23 
24 /**
25  * @file
26  * @ingroup libavf
27  * Main libavformat public API header
28  */
29 
30 /**
31  * @defgroup libavf I/O and Muxing/Demuxing Library
32  * @{
33  *
34  * Libavformat (lavf) is a library for dealing with various media container
35  * formats. Its main two purposes are demuxing - i.e. splitting a media file
36  * into component streams, and the reverse process of muxing - writing supplied
37  * data in a specified container format. It also has an @ref lavf_io
38  * "I/O module" which supports a number of protocols for accessing the data (e.g.
39  * file, tcp, http and others). Before using lavf, you need to call
40  * av_register_all() to register all compiled muxers, demuxers and protocols.
41  * Unless you are absolutely sure you won't use libavformat's network
42  * capabilities, you should also call avformat_network_init().
43  *
44  * A supported input format is described by an AVInputFormat struct, conversely
45  * an output format is described by AVOutputFormat. You can iterate over all
46  * registered input/output formats using the av_iformat_next() /
47  * av_oformat_next() functions. The protocols layer is not part of the public
48  * API, so you can only get the names of supported protocols with the
49  * avio_enum_protocols() function.
50  *
51  * Main lavf structure used for both muxing and demuxing is AVFormatContext,
52  * which exports all information about the file being read or written. As with
53  * most Libavformat structures, its size is not part of public ABI, so it cannot be
54  * allocated on stack or directly with av_malloc(). To create an
55  * AVFormatContext, use avformat_alloc_context() (some functions, like
56  * avformat_open_input() might do that for you).
57  *
58  * Most importantly an AVFormatContext contains:
59  * @li the @ref AVFormatContext.iformat "input" or @ref AVFormatContext.oformat
60  * "output" format. It is either autodetected or set by user for input;
61  * always set by user for output.
62  * @li an @ref AVFormatContext.streams "array" of AVStreams, which describe all
63  * elementary streams stored in the file. AVStreams are typically referred to
64  * using their index in this array.
65  * @li an @ref AVFormatContext.pb "I/O context". It is either opened by lavf or
66  * set by user for input, always set by user for output (unless you are dealing
67  * with an AVFMT_NOFILE format).
68  *
69  * @section lavf_options Passing options to (de)muxers
70  * Lavf allows to configure muxers and demuxers using the @ref avoptions
71  * mechanism. Generic (format-independent) libavformat options are provided by
72  * AVFormatContext, they can be examined from a user program by calling
73  * av_opt_next() / av_opt_find() on an allocated AVFormatContext (or its AVClass
74  * from avformat_get_class()). Private (format-specific) options are provided by
75  * AVFormatContext.priv_data if and only if AVInputFormat.priv_class /
76  * AVOutputFormat.priv_class of the corresponding format struct is non-NULL.
77  * Further options may be provided by the @ref AVFormatContext.pb "I/O context",
78  * if its AVClass is non-NULL, and the protocols layer. See the discussion on
79  * nesting in @ref avoptions documentation to learn how to access those.
80  *
81  * @defgroup lavf_decoding Demuxing
82  * @{
83  * Demuxers read a media file and split it into chunks of data (@em packets). A
84  * @ref AVPacket "packet" contains one or more encoded frames which belongs to a
85  * single elementary stream. In the lavf API this process is represented by the
86  * avformat_open_input() function for opening a file, av_read_frame() for
87  * reading a single packet and finally avformat_close_input(), which does the
88  * cleanup.
89  *
90  * @section lavf_decoding_open Opening a media file
91  * The minimum information required to open a file is its URL or filename, which
92  * is passed to avformat_open_input(), as in the following code:
93  * @code
94  * const char    *url = "in.mp3";
95  * AVFormatContext *s = NULL;
96  * int ret = avformat_open_input(&s, url, NULL, NULL);
97  * if (ret < 0)
98  *     abort();
99  * @endcode
100  * The above code attempts to allocate an AVFormatContext, open the
101  * specified file (autodetecting the format) and read the header, exporting the
102  * information stored there into s. Some formats do not have a header or do not
103  * store enough information there, so it is recommended that you call the
104  * avformat_find_stream_info() function which tries to read and decode a few
105  * frames to find missing information.
106  *
107  * In some cases you might want to preallocate an AVFormatContext yourself with
108  * avformat_alloc_context() and do some tweaking on it before passing it to
109  * avformat_open_input(). One such case is when you want to use custom functions
110  * for reading input data instead of lavf internal I/O layer.
111  * To do that, create your own AVIOContext with avio_alloc_context(), passing
112  * your reading callbacks to it. Then set the @em pb field of your
113  * AVFormatContext to newly created AVIOContext.
114  *
115  * Since the format of the opened file is in general not known until after
116  * avformat_open_input() has returned, it is not possible to set demuxer private
117  * options on a preallocated context. Instead, the options should be passed to
118  * avformat_open_input() wrapped in an AVDictionary:
119  * @code
120  * AVDictionary *options = NULL;
121  * av_dict_set(&options, "video_size", "640x480", 0);
122  * av_dict_set(&options, "pixel_format", "rgb24", 0);
123  *
124  * if (avformat_open_input(&s, url, NULL, &options) < 0)
125  *     abort();
126  * av_dict_free(&options);
127  * @endcode
128  * This code passes the private options 'video_size' and 'pixel_format' to the
129  * demuxer. They would be necessary for e.g. the rawvideo demuxer, since it
130  * cannot know how to interpret raw video data otherwise. If the format turns
131  * out to be something different than raw video, those options will not be
132  * recognized by the demuxer and therefore will not be applied. Such unrecognized
133  * options are then returned in the options dictionary (recognized options are
134  * consumed). The calling program can handle such unrecognized options as it
135  * wishes, e.g.
136  * @code
137  * AVDictionaryEntry *e;
138  * if (e = av_dict_get(options, "", NULL, AV_DICT_IGNORE_SUFFIX)) {
139  *     fprintf(stderr, "Option %s not recognized by the demuxer.\n", e->key);
140  *     abort();
141  * }
142  * @endcode
143  *
144  * After you have finished reading the file, you must close it with
145  * avformat_close_input(). It will free everything associated with the file.
146  *
147  * @section lavf_decoding_read Reading from an opened file
148  * Reading data from an opened AVFormatContext is done by repeatedly calling
149  * av_read_frame() on it. Each call, if successful, will return an AVPacket
150  * containing encoded data for one AVStream, identified by
151  * AVPacket.stream_index. This packet may be passed straight into the libavcodec
152  * decoding functions avcodec_decode_video2(), avcodec_decode_audio4() or
153  * avcodec_decode_subtitle2() if the caller wishes to decode the data.
154  *
155  * AVPacket.pts, AVPacket.dts and AVPacket.duration timing information will be
156  * set if known. They may also be unset (i.e. AV_NOPTS_VALUE for
157  * pts/dts, 0 for duration) if the stream does not provide them. The timing
158  * information will be in AVStream.time_base units, i.e. it has to be
159  * multiplied by the timebase to convert them to seconds.
160  *
161  * If AVPacket.buf is set on the returned packet, then the packet is
162  * allocated dynamically and the user may keep it indefinitely.
163  * Otherwise, if AVPacket.buf is NULL, the packet data is backed by a
164  * static storage somewhere inside the demuxer and the packet is only valid
165  * until the next av_read_frame() call or closing the file. If the caller
166  * requires a longer lifetime, av_dup_packet() will make an av_malloc()ed copy
167  * of it.
168  * In both cases, the packet must be freed with av_free_packet() when it is no
169  * longer needed.
170  *
171  * @section lavf_decoding_seek Seeking
172  * @}
173  *
174  * @defgroup lavf_encoding Muxing
175  * @{
176  * Muxers take encoded data in the form of @ref AVPacket "AVPackets" and write
177  * it into files or other output bytestreams in the specified container format.
178  *
179  * The main API functions for muxing are avformat_write_header() for writing the
180  * file header, av_write_frame() / av_interleaved_write_frame() for writing the
181  * packets and av_write_trailer() for finalizing the file.
182  *
183  * At the beginning of the muxing process, the caller must first call
184  * avformat_alloc_context() to create a muxing context. The caller then sets up
185  * the muxer by filling the various fields in this context:
186  *
187  * - The @ref AVFormatContext.oformat "oformat" field must be set to select the
188  *   muxer that will be used.
189  * - Unless the format is of the AVFMT_NOFILE type, the @ref AVFormatContext.pb
190  *   "pb" field must be set to an opened IO context, either returned from
191  *   avio_open2() or a custom one.
192  * - Unless the format is of the AVFMT_NOSTREAMS type, at least one stream must
193  *   be created with the avformat_new_stream() function. The caller should fill
194  *   the @ref AVStream.codec "stream codec context" information, such as the
195  *   codec @ref AVCodecContext.codec_type "type", @ref AVCodecContext.codec_id
196  *   "id" and other parameters (e.g. width / height, the pixel or sample format,
197  *   etc.) as known. The @ref AVStream.time_base "stream timebase" should
198  *   be set to the timebase that the caller desires to use for this stream (note
199  *   that the timebase actually used by the muxer can be different, as will be
200  *   described later).
201  * - The caller may fill in additional information, such as @ref
202  *   AVFormatContext.metadata "global" or @ref AVStream.metadata "per-stream"
203  *   metadata, @ref AVFormatContext.chapters "chapters", @ref
204  *   AVFormatContext.programs "programs", etc. as described in the
205  *   AVFormatContext documentation. Whether such information will actually be
206  *   stored in the output depends on what the container format and the muxer
207  *   support.
208  *
209  * When the muxing context is fully set up, the caller must call
210  * avformat_write_header() to initialize the muxer internals and write the file
211  * header. Whether anything actually is written to the IO context at this step
212  * depends on the muxer, but this function must always be called. Any muxer
213  * private options must be passed in the options parameter to this function.
214  *
215  * The data is then sent to the muxer by repeatedly calling av_write_frame() or
216  * av_interleaved_write_frame() (consult those functions' documentation for
217  * discussion on the difference between them; only one of them may be used with
218  * a single muxing context, they should not be mixed). Do note that the timing
219  * information on the packets sent to the muxer must be in the corresponding
220  * AVStream's timebase. That timebase is set by the muxer (in the
221  * avformat_write_header() step) and may be different from the timebase
222  * requested by the caller.
223  *
224  * Once all the data has been written, the caller must call av_write_trailer()
225  * to flush any buffered packets and finalize the output file, then close the IO
226  * context (if any) and finally free the muxing context with
227  * avformat_free_context().
228  * @}
229  *
230  * @defgroup lavf_io I/O Read/Write
231  * @{
232  * @}
233  *
234  * @defgroup lavf_codec Demuxers
235  * @{
236  * @defgroup lavf_codec_native Native Demuxers
237  * @{
238  * @}
239  * @defgroup lavf_codec_wrappers External library wrappers
240  * @{
241  * @}
242  * @}
243  * @defgroup lavf_protos I/O Protocols
244  * @{
245  * @}
246  * @defgroup lavf_internal Internal
247  * @{
248  * @}
249  * @}
250  *
251  */
252 
253 module ffmpeg.libavformat.avformat;
254 
255 import std.stdint;
256 import std.bitmanip;
257 import std.stdio;
258 import core.vararg;
259 
260 import ffmpeg.libavutil.avutil;
261 import ffmpeg.libavcodec.avcodec;
262 import ffmpeg.libavformat.avio;
263 import ffmpeg.libavformat.avformat_version;
264 import ffmpeg.libavformat.internal;
265 import ffmpeg.libavdevice.avdevice;
266 
267 @nogc nothrow extern(C):
268 /**
269  * @defgroup metadata_api Public Metadata API
270  * @{
271  * @ingroup libavf
272  * The metadata API allows libavformat to export metadata tags to a client
273  * application when demuxing. Conversely it allows a client application to
274  * set metadata when muxing.
275  *
276  * Metadata is exported or set as pairs of key/value strings in the 'metadata'
277  * fields of the AVFormatContext, AVStream, AVChapter and AVProgram structs
278  * using the @ref lavu_dict "AVDictionary" API. Like all strings in FFmpeg,
279  * metadata is assumed to be UTF-8 encoded Unicode. Note that metadata
280  * exported by demuxers isn't checked to be valid UTF-8 in most cases.
281  *
282  * Important concepts to keep in mind:
283  * -  Keys are unique; there can never be 2 tags with the same key. This is
284  *    also meant semantically, i.e., a demuxer should not knowingly produce
285  *    several keys that are literally different but semantically identical.
286  *    E.g., key=Author5, key=Author6. In this example, all authors must be
287  *    placed in the same tag.
288  * -  Metadata is flat, not hierarchical; there are no subtags. If you
289  *    want to store, e.g., the email address of the child of producer Alice
290  *    and actor Bob, that could have key=alice_and_bobs_childs_email_address.
291  * -  Several modifiers can be applied to the tag name. This is done by
292  *    appending a dash character ('-') and the modifier name in the order
293  *    they appear in the list below -- e.g. foo-eng-sort, not foo-sort-eng.
294  *    -  language -- a tag whose value is localized for a particular language
295  *       is appended with the ISO 639-2/B 3-letter language code.
296  *       For example: Author-ger=Michael, Author-eng=Mike
297  *       The original/default language is in the unqualified "Author" tag.
298  *       A demuxer should set a default if it sets any translated tag.
299  *    -  sorting  -- a modified version of a tag that should be used for
300  *       sorting will have '-sort' appended. E.g. artist="The Beatles",
301  *       artist-sort="Beatles, The".
302  * - Some protocols and demuxers support metadata updates. After a successful
303  *   call to av_read_packet(), AVFormatContext.event_flags or AVStream.event_flags
304  *   will be updated to indicate if metadata changed. In order to detect metadata
305  *   changes on a stream, you need to loop through all streams in the AVFormatContext
306  *   and check their individual event_flags.
307  *
308  * -  Demuxers attempt to export metadata in a generic format, however tags
309  *    with no generic equivalents are left as they are stored in the container.
310  *    Follows a list of generic tag names:
311  *
312  @verbatim
313  album        -- name of the set this work belongs to
314  album_artist -- main creator of the set/album, if different from artist.
315                  e.g. "Various Artists" for compilation albums.
316  artist       -- main creator of the work
317  comment      -- any additional description of the file.
318  composer     -- who composed the work, if different from artist.
319  copyright    -- name of copyright holder.
320  creation_time-- date when the file was created, preferably in ISO 8601.
321  date         -- date when the work was created, preferably in ISO 8601.
322  disc         -- number of a subset, e.g. disc in a multi-disc collection.
323  encoder      -- name/settings of the software/hardware that produced the file.
324  encoded_by   -- person/group who created the file.
325  filename     -- original name of the file.
326  genre        -- <self-evident>.
327  language     -- main language in which the work is performed, preferably
328                  in ISO 639-2 format. Multiple languages can be specified by
329                  separating them with commas.
330  performer    -- artist who performed the work, if different from artist.
331                  E.g for "Also sprach Zarathustra", artist would be "Richard
332                  Strauss" and performer "London Philharmonic Orchestra".
333  publisher    -- name of the label/publisher.
334  service_name     -- name of the service in broadcasting (channel name).
335  service_provider -- name of the service provider in broadcasting.
336  title        -- name of the work.
337  track        -- number of this work in the set, can be in form current/total.
338  variant_bitrate -- the total bitrate of the bitrate variant that the current stream is part of
339  @endverbatim
340  *
341  * Look in the examples section for an application example how to use the Metadata API.
342  *
343  * @}
344  */
345 
346 /* packet functions */
347 
348 
349 /**
350  * Allocate and read the payload of a packet and initialize its
351  * fields with default values.
352  *
353  * @param s    associated IO context
354  * @param pkt packet
355  * @param size desired payload size
356  * @return >0 (read size) if OK, AVERROR_xxx otherwise
357  */
358 int av_get_packet(AVIOContext *s, AVPacket *pkt, int size);
359 
360 
361 /**
362  * Read data and append it to the current content of the AVPacket.
363  * If pkt->size is 0 this is identical to av_get_packet.
364  * Note that this uses av_grow_packet and thus involves a realloc
365  * which is inefficient. Thus this function should only be used
366  * when there is no reasonable way to know (an upper bound of)
367  * the final size.
368  *
369  * @param s    associated IO context
370  * @param pkt packet
371  * @param size amount of data to read
372  * @return >0 (read size) if OK, AVERROR_xxx otherwise, previous data
373  *         will not be lost even if an error occurs.
374  */
375 int av_append_packet(AVIOContext *s, AVPacket *pkt, int size);
376 
377 static if (FF_API_LAVF_FRAC) {
378 /*************************************************/
379 /* fractional numbers for exact pts handling */
380 
381 /**
382  * The exact value of the fractional number is: 'val + num / den'.
383  * num is assumed to be 0 <= num < den.
384  */
385 struct AVFrac {
386     int64_t val, num, den;
387 }
388 }
389 
390 /*************************************************/
391 /* input/output formats */
392 
393 struct AVCodecTag;
394 
395 /**
396  * This structure contains the data a format has to probe a file.
397  */
398 struct AVProbeData {
399     const char *filename;
400     ubyte *buf; /**< Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero. */
401     int buf_size;       /**< Size of buf except extra allocated bytes */
402     uint8_t *mime_type; /**< mime_type, when known. */
403 }
404 
405 enum AVPROBE_SCORE_RETRY = (AVPROBE_SCORE_MAX/4);
406 enum AVPROBE_SCORE_STREAM_RETRY=(AVPROBE_SCORE_MAX/4-1);
407 
408 enum AVPROBE_SCORE_EXTENSION= 50; ///< score for file extension
409 enum AVPROBE_SCORE_MIME   =   75; ///< score for file mime type
410 enum AVPROBE_SCORE_MAX =     100; ///< maximum score
411 
412 enum AVPROBE_PADDING_SIZE = 32;             ///< extra allocated bytes at the end of the probe buffer
413 
414 /// Demuxer will use avio_open, no opened file should be provided by the caller.
415 enum AVFMT_NOFILE      = 0x0001;
416 enum AVFMT_NEEDNUMBER  = 0x0002; /**< Needs '%d' in filename. */
417 enum AVFMT_SHOW_IDS    = 0x0008; /**< Show format stream IDs numbers. */
418 static if(FF_API_LAVF_FMT_RAWPICTURE){
419     enum AVFMT_RAWPICTURE  = 0x0020; /**< Format wants AVPicture structure for
420                                           raw picture data. */
421 }
422 enum AVFMT_GLOBALHEADER= 0x0040; /**< Format wants global header. */
423 enum AVFMT_NOTIMESTAMPS= 0x0080; /**< Format does not need / have any timestamps. */
424 enum AVFMT_GENERIC_INDEX=0x0100; /**< Use generic index building code. */
425 enum AVFMT_TS_DISCONT  = 0x0200; /**< Format allows timestamp discontinuities. Note, muxers always require valid (monotone) timestamps */
426 enum AVFMT_VARIABLE_FPS= 0x0400; /**< Format allows variable fps. */
427 enum AVFMT_NODIMENSIONS= 0x0800; /**< Format does not need width/height */
428 enum AVFMT_NOSTREAMS   = 0x1000; /**< Format does not require any streams */
429 enum AVFMT_NOBINSEARCH = 0x2000; /**< Format does not allow to fallback to binary search via read_timestamp */
430 enum AVFMT_NOGENSEARCH = 0x4000; /**< Format does not allow to fallback to generic search */
431 enum AVFMT_NO_BYTE_SEEK= 0x8000; /**< Format does not allow seeking by bytes */
432 enum AVFMT_ALLOW_FLUSH =0x10000; /**< Format allows flushing. If not set, the muxer will not receive a NULL packet in the write_packet function. */
433 enum AVFMT_TS_NONSTRICT = 0x20000;
434                                    /**< Format does not require strictly
435                                         increasing timestamps, but they must
436                                         still be monotonic */
437 enum AVFMT_TS_NEGATIVE =0x40000; /**< Format allows muxing negative
438                                         timestamps. If not set the timestamp
439                                         will be shifted in av_write_frame and
440                                         av_interleaved_write_frame so they
441                                         start from 0.
442                                         The user or muxer can override this through
443                                         AVFormatContext.avoid_negative_ts
444                                         */
445 
446 enum AVFMT_SEEK_TO_PTS = 0x4000000; /**< Seeking is based on PTS */
447 
448 /**
449  * @addtogroup lavf_encoding
450  * @{
451  */
452 struct AVOutputFormat {
453     const char *name;
454     /**
455      * Descriptive name for the format, meant to be more human-readable
456      * than name. You should use the NULL_IF_CONFIG_SMALL() macro
457      * to define it.
458      */
459     const char *long_name;
460     const char *mime_type;
461     const char *extensions; /**< comma-separated filename extensions */
462     /* output support */
463     AVCodecID audio_codec;    /**< default audio codec */
464     AVCodecID video_codec;    /**< default video codec */
465     AVCodecID subtitle_codec; /**< default subtitle codec */
466     /**
467      * can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER, AVFMT_RAWPICTURE,
468      * AVFMT_GLOBALHEADER, AVFMT_NOTIMESTAMPS, AVFMT_VARIABLE_FPS,
469      * AVFMT_NODIMENSIONS, AVFMT_NOSTREAMS, AVFMT_ALLOW_FLUSH,
470      * AVFMT_TS_NONSTRICT
471      */
472     int flags;
473 
474     /**
475      * List of supported codec_id-codec_tag pairs, ordered by "better
476      * choice first". The arrays are all terminated by AV_CODEC_ID_NONE.
477      */
478     const AVCodecTag **codec_tag;
479 
480 
481     const AVClass *priv_class; ///< AVClass for the private context
482 
483     /*****************************************************************
484      * No fields below this line are part of the public API. They
485      * may not be used outside of libavformat and can be changed and
486      * removed at will.
487      * New public fields should be added right above.
488      *****************************************************************
489      */
490     AVOutputFormat *next;
491     /**
492      * size of private data so that it can be allocated in the wrapper
493      */
494     int priv_data_size;
495 
496     int function(AVFormatContext *) write_header;
497     /**
498      * Write a packet. If AVFMT_ALLOW_FLUSH is set in flags,
499      * pkt can be NULL in order to flush data buffered in the muxer.
500      * When flushing, return 0 if there still is more data to flush,
501      * or 1 if everything was flushed and there is no more buffered
502      * data.
503      */
504     int function(AVFormatContext *, AVPacket *pkt) write_packet;
505     int function(AVFormatContext *) write_trailer;
506     /**
507      * Currently only used to set pixel format if not YUV420P.
508      */
509     int function(AVFormatContext *, AVPacket *out_pkt,
510                              AVPacket *in_pkt, int flush) interleave_packet;
511     /**
512      * Test if the given codec can be stored in this container.
513      *
514      * @return 1 if the codec is supported, 0 if it is not.
515      *         A negative number if unknown.
516      *         MKTAG('A', 'P', 'I', 'C') if the codec is only supported as AV_DISPOSITION_ATTACHED_PIC
517      */
518     int function(AVCodecID id, int std_compliance) query_codec;
519 
520     void function (AVFormatContext *s, int stream,
521                                  int64_t *dts, int64_t *wall) get_output_timestamp;
522     /**
523      * Allows sending messages from application to device.
524      */
525     int function(AVFormatContext *s, int type,
526                            void *data, size_t data_size) control_message;
527 
528     /**
529      * Write an uncoded AVFrame.
530      *
531      * See av_write_uncoded_frame() for details.
532      *
533      * The library will free *frame afterwards, but the muxer can prevent it
534      * by setting the pointer to NULL.
535      */
536     int function(AVFormatContext *, int stream_index,
537                                AVFrame **frame, uint flags) write_uncoded_frame;
538     /**
539      * Returns device list with it properties.
540      * @see avdevice_list_devices() for more details.
541      */
542     int function(AVFormatContext *s, AVDeviceInfoList *device_list) get_device_list;
543     /**
544      * Initialize device capabilities submodule.
545      * @see avdevice_capabilities_create() for more details.
546      */
547     int function(AVFormatContext *s, AVDeviceCapabilitiesQuery *caps) create_device_capabilities;
548     /**
549      * Free device capabilities submodule.
550      * @see avdevice_capabilities_free() for more details.
551      */
552     int function(AVFormatContext *s, AVDeviceCapabilitiesQuery *caps) free_device_capabilities;
553     AVCodecID data_codec; /**< default data codec */
554     /**
555      * Initialize format. May allocate data here, and set any AVFormatContext or
556      * AVStream parameters that need to be set before packets are sent.
557      * This method must not write output.
558      *
559      * Any allocations made here must be freed in deinit().
560      */
561     int function(AVFormatContext *) init;
562     /**
563      * Deinitialize format. If present, this is called whenever the muxer is being
564      * destroyed, regardless of whether or not the header has been written.
565      *
566      * If a trailer is being written, this is called after write_trailer().
567      *
568      * This is called if init() fails as well.
569      */
570     void function(AVFormatContext *) deinit;
571     /**
572      * Set up any necessary bitstream filtering and extract any extra data needed
573      * for the global header.
574      * Return 0 if more packets from this stream must be checked; 1 if not.
575      */
576     int function(AVFormatContext *, const AVPacket *pkt) check_bitstream;
577 }
578 /**
579  * @}
580  */
581 
582 /**
583  * @addtogroup lavf_decoding
584  * @{
585  */
586 struct AVInputFormat {
587     /**
588      * A comma separated list of short names for the format. New names
589      * may be appended with a minor bump.
590      */
591     const char *name;
592 
593     /**
594      * Descriptive name for the format, meant to be more human-readable
595      * than name. You should use the NULL_IF_CONFIG_SMALL() macro
596      * to define it.
597      */
598     const char *long_name;
599 
600     /**
601      * Can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER, AVFMT_SHOW_IDS,
602      * AVFMT_GENERIC_INDEX, AVFMT_TS_DISCONT, AVFMT_NOBINSEARCH,
603      * AVFMT_NOGENSEARCH, AVFMT_NO_BYTE_SEEK, AVFMT_SEEK_TO_PTS.
604      */
605     int flags;
606 
607     /**
608      * If extensions are defined, then no probe is done. You should
609      * usually not use extension format guessing because it is not
610      * reliable enough
611      */
612     const char *extensions;
613 
614     const AVCodecTag **codec_tag;
615 
616     const AVClass *priv_class; ///< AVClass for the private context
617 
618     /**
619      * Comma-separated list of mime types.
620      * It is used check for matching mime types while probing.
621      * @see av_probe_input_format2
622      */
623     const char *mime_type;
624 
625     /*****************************************************************
626      * No fields below this line are part of the public API. They
627      * may not be used outside of libavformat and can be changed and
628      * removed at will.
629      * New public fields should be added right above.
630      *****************************************************************
631      */
632     AVInputFormat *next;
633 
634     /**
635      * Raw demuxers store their codec ID here.
636      */
637     int raw_codec_id;
638 
639     /**
640      * Size of private data so that it can be allocated in the wrapper.
641      */
642     int priv_data_size;
643 
644     /**
645      * Tell if a given file has a chance of being parsed as this format.
646      * The buffer provided is guaranteed to be AVPROBE_PADDING_SIZE bytes
647      * big so you do not have to check for that unless you need more.
648      */
649     int function(AVProbeData *) read_probe;
650 
651     /**
652      * Read the format header and initialize the AVFormatContext
653      * structure. Return 0 if OK. Only used in raw format right
654      * now. 'avformat_new_stream' should be called to create new streams.
655      */
656     int function(AVFormatContext *) read_header;
657 
658     /**
659      * Read one packet and put it in 'pkt'. pts and flags are also
660      * set. 'avformat_new_stream' can be called only if the flag
661      * AVFMTCTX_NOHEADER is used and only in the calling thread (not in a
662      * background thread).
663      * @return 0 on success, < 0 on error.
664      *         When returning an error, pkt must not have been allocated
665      *         or must be freed before returning
666      */
667     int function(AVFormatContext *, AVPacket *pkt) read_packet;
668 
669     /**
670      * Close the stream. The AVFormatContext and AVStreams are not
671      * freed by this function
672      */
673     int function(AVFormatContext *) read_close;
674 
675     /**
676      * Seek to a given timestamp relative to the frames in
677      * stream component stream_index.
678      * @param stream_index Must not be -1.
679      * @param flags Selects which direction should be preferred if no exact
680      *              match is available.
681      * @return >= 0 on success (but not necessarily the new offset)
682      */
683     int function(AVFormatContext *,
684                      int stream_index, int64_t timestamp, int flags) read_seek;
685 
686     /**
687      * Get the next timestamp in stream[stream_index].time_base units.
688      * @return the timestamp or AV_NOPTS_VALUE if an error occurred
689      */
690     int64_t function(AVFormatContext *s, int stream_index,
691                               int64_t *pos, int64_t pos_limit) read_timestamp;
692 
693     /**
694      * Start/resume playing - only meaningful if using a network-based format
695      * (RTSP).
696      */
697     int function(AVFormatContext *) read_play;
698 
699     /**
700      * Pause playing - only meaningful if using a network-based format
701      * (RTSP).
702      */
703     int function(AVFormatContext *) read_pause;
704 
705     /**
706      * Seek to timestamp ts.
707      * Seeking will be done so that the point from which all active streams
708      * can be presented successfully will be closest to ts and within min/max_ts.
709      * Active streams are all streams that have AVStream.discard < AVDISCARD_ALL.
710      */
711     int function(AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
712         read_seek2;
713 
714     /**
715      * Returns device list with it properties.
716      * @see avdevice_list_devices() for more details.
717      */
718     int function(AVFormatContext *s, AVDeviceInfoList *device_list) get_device_list;
719 
720     /**
721      * Initialize device capabilities submodule.
722      * @see avdevice_capabilities_create() for more details.
723      */
724     int function(AVFormatContext *s, AVDeviceCapabilitiesQuery *caps) create_device_capabilities;
725 
726     /**
727      * Free device capabilities submodule.
728      * @see avdevice_capabilities_free() for more details.
729      */
730     int function(AVFormatContext *s, AVDeviceCapabilitiesQuery *caps) free_device_capabilities;
731 }
732 /**
733  * @}
734  */
735 
736 enum AVStreamParseType:int {
737     AVSTREAM_PARSE_NONE,
738     AVSTREAM_PARSE_FULL,       /**< full parsing and repack */
739     AVSTREAM_PARSE_HEADERS,    /**< Only parse headers, do not repack. */
740     AVSTREAM_PARSE_TIMESTAMPS, /**< full parsing and interpolation of timestamps for frames not starting on a packet boundary */
741     AVSTREAM_PARSE_FULL_ONCE,  /**< full parsing and repack of the first frame only, only implemented for H.264 currently */
742     AVSTREAM_PARSE_FULL_RAW=MKTAG!(0,'R','A','W')       /**< full parsing and repack with timestamp and position generation by parser for raw
743                                                              this assumes that each packet in the file contains no demuxer level headers and
744                                                              just codec level data, otherwise position generation would fail */
745 }
746 
747 struct AVIndexEntry {
748     int64_t pos;
749     int64_t timestamp;        /**<
750                                * Timestamp in AVStream.time_base units, preferably the time from which on correctly decoded frames are available
751                                * when seeking to this entry. That means preferable PTS on keyframe based formats.
752                                * But demuxers can choose to store a different timestamp, if it is more convenient for the implementation or nothing better
753                                * is known
754                                */
755 //#define AVINDEX_KEYFRAME 0x0001
756     mixin( bitfields!(
757     int, "flags", 2,
758     int, "size", 30)); //Yeah, trying to keep the size of this small to reduce memory requirements (it is 24 vs. 32 bytes due to possible 8-byte alignment).
759     int min_distance;  /**< Minimum distance between this and the previous keyframe, used to avoid unneeded searching. */
760 }
761 
762 enum AV_DISPOSITION_DEFAULT = 0x0001;
763 enum AV_DISPOSITION_DUB     = 0x0002;
764 enum AV_DISPOSITION_ORIGINAL= 0x0004;
765 enum AV_DISPOSITION_COMMENT = 0x0008;
766 enum AV_DISPOSITION_LYRICS  = 0x0010;
767 enum AV_DISPOSITION_KARAOKE = 0x0020;
768 
769 /**
770  * Track should be used during playback by default.
771  * Useful for subtitle track that should be displayed
772  * even when user did not explicitly ask for subtitles.
773  */
774 enum AV_DISPOSITION_FORCED  = 0x0040;
775 enum AV_DISPOSITION_HEARING_IMPAIRED =0x0080;  /**< stream for hearing impaired audiences */
776 enum AV_DISPOSITION_VISUAL_IMPAIRED  =0x0100;  /**< stream for visual impaired audiences */
777 enum AV_DISPOSITION_CLEAN_EFFECTS    =0x0200;  /**< stream without voice */
778 /**
779  * The stream is stored in the file as an attached picture/"cover art" (e.g.
780  * APIC frame in ID3v2). The single packet associated with it will be returned
781  * among the first few packets read from the file unless seeking takes place.
782  * It can also be accessed at any time in AVStream.attached_pic.
783  */
784 enum AV_DISPOSITION_ATTACHED_PIC     =0x0400;
785 
786 struct AVStreamInternal;
787 
788 /**
789  * To specify text track kind (different from subtitles default).
790  */
791 enum AV_DISPOSITION_CAPTIONS    =0x10000;
792 enum AV_DISPOSITION_DESCRIPTIONS=0x20000;
793 enum AV_DISPOSITION_METADATA    =0x40000;
794 
795 /**
796  * Options for behavior on timestamp wrap detection.
797  */
798 enum AV_PTS_WRAP_IGNORE  =    0;   ///< ignore the wrap
799 enum AV_PTS_WRAP_ADD_OFFSET = 1;   ///< add the format specific offset on wrap detection
800 enum AV_PTS_WRAP_SUB_OFFSET = -1;  ///< subtract the format specific offset on wrap detection
801 
802 
803 /**
804  * Stream structure.
805  * New fields can be added to the end with minor version bumps.
806  * Removal, reordering and changes to existing fields require a major
807  * version bump.
808  * sizeof(AVStream) must not be used outside libav*.
809  */
810 struct AVStream {
811     int index;    /**< stream index in AVFormatContext */
812     /**
813      * Format-specific stream ID.
814      * decoding: set by libavformat
815      * encoding: set by the user, replaced by libavformat if left unset
816      */
817     int id;
818     /**
819      * Codec context associated with this stream. Allocated and freed by
820      * libavformat.
821      *
822      * - decoding: The demuxer exports codec information stored in the headers
823      *             here.
824      * - encoding: The user sets codec information, the muxer writes it to the
825      *             output. Mandatory fields as specified in AVCodecContext
826      *             documentation must be set even if this AVCodecContext is
827      *             not actually used for encoding.
828      */
829     AVCodecContext *codec;
830     void *priv_data;
831 
832 static if(FF_API_LAVF_FRAC) {
833     /**
834      * @deprecated this field is unused
835      */
836     deprecated
837     AVFrac pts;
838 }
839 
840     /**
841      * This is the fundamental unit of time (in seconds) in terms
842      * of which frame timestamps are represented.
843      *
844      * decoding: set by libavformat
845      * encoding: May be set by the caller before avformat_write_header() to
846      *           provide a hint to the muxer about the desired timebase. In
847      *           avformat_write_header(), the muxer will overwrite this field
848      *           with the timebase that will actually be used for the timestamps
849      *           written into the file (which may or may not be related to the
850      *           user-provided one, depending on the format).
851      */
852     AVRational time_base;
853 
854     /**
855      * Decoding: pts of the first frame of the stream in presentation order, in stream time base.
856      * Only set this if you are absolutely 100% sure that the value you set
857      * it to really is the pts of the first frame.
858      * This may be undefined (AV_NOPTS_VALUE).
859      * @note The ASF header does NOT contain a correct start_time the ASF
860      * demuxer must NOT set this.
861      */
862     int64_t start_time;
863 
864     /**
865      * Decoding: duration of the stream, in stream time base.
866      * If a source file does not specify a duration, but does specify
867      * a bitrate, this value will be estimated from bitrate and file size.
868      */
869     int64_t duration;
870 
871     int64_t nb_frames;                 ///< number of frames in this stream if known or 0
872 
873     int disposition; /**< AV_DISPOSITION_* bit field */
874 
875     AVDiscard discard; ///< Selects which packets can be discarded at will and do not need to be demuxed.
876 
877     /**
878      * sample aspect ratio (0 if unknown)
879      * - encoding: Set by user.
880      * - decoding: Set by libavformat.
881      */
882     AVRational sample_aspect_ratio;
883 
884     AVDictionary *metadata;
885 
886     /**
887      * Average framerate
888      *
889      * - demuxing: May be set by libavformat when creating the stream or in
890      *             avformat_find_stream_info().
891      * - muxing: May be set by the caller before avformat_write_header().
892      */
893     AVRational avg_frame_rate;
894 
895     /**
896      * For streams with AV_DISPOSITION_ATTACHED_PIC disposition, this packet
897      * will contain the attached picture.
898      *
899      * decoding: set by libavformat, must not be modified by the caller.
900      * encoding: unused
901      */
902     AVPacket attached_pic;
903 
904     /**
905      * An array of side data that applies to the whole stream (i.e. the
906      * container does not allow it to change between packets).
907      *
908      * There may be no overlap between the side data in this array and side data
909      * in the packets. I.e. a given side data is either exported by the muxer
910      * (demuxing) / set by the caller (muxing) in this array, then it never
911      * appears in the packets, or the side data is exported / sent through
912      * the packets (always in the first packet where the value becomes known or
913      * changes), then it does not appear in this array.
914      *
915      * - demuxing: Set by libavformat when the stream is created.
916      * - muxing: May be set by the caller before avformat_write_header().
917      *
918      * Freed by libavformat in avformat_free_context().
919      *
920      * @see av_format_inject_global_side_data()
921      */
922     AVPacketSideData *side_data;
923     /**
924      * The number of elements in the AVStream.side_data array.
925      */
926     int            nb_side_data;
927 
928     /**
929      * Flags for the user to detect events happening on the stream. Flags must
930      * be cleared by the user once the event has been handled.
931      * A combination of AVSTREAM_EVENT_FLAG_*.
932      */
933     int event_flags;
934 //#define AVSTREAM_EVENT_FLAG_METADATA_UPDATED 0x0001 ///< The call resulted in updated metadata.
935 
936     /*****************************************************************
937      * All fields below this line are not part of the public API. They
938      * may not be used outside of libavformat and can be changed and
939      * removed at will.
940      * New public fields should be added right above.
941      *****************************************************************
942      */
943 
944     /**
945      * Stream information used internally by av_find_stream_info()
946     */
947 //#define MAX_STD_TIMEBASES (60*12+6)
948     struct Info {
949         int64_t last_dts;
950         int64_t duration_gcd;
951         int duration_count;
952         int64_t rfps_duration_sum;
953         double function() [2][MAX_STD_TIMEBASES]duration_error;
954         int64_t codec_info_duration;
955         int64_t codec_info_duration_fields;
956 
957         /**
958          * 0  -> decoder has not been searched for yet.
959          * >0 -> decoder found
960          * <0 -> decoder with codec_id == -found_decoder has not been found
961          */
962         int found_decoder;
963 
964         int64_t last_duration;
965 
966         /**
967          * Those are used for average framerate estimation.
968          */
969         int64_t fps_first_dts;
970         int     fps_first_dts_idx;
971         int64_t fps_last_dts;
972         int     fps_last_dts_idx;
973 
974     }
975     Info* info;
976 
977     int pts_wrap_bits; /**< number of bits in pts (used for wrapping control) */
978 
979     // Timestamp generation support:
980     /**
981      * Timestamp corresponding to the last dts sync point.
982      *
983      * Initialized when AVCodecParserContext.dts_sync_point >= 0 and
984      * a DTS is received from the underlying container. Otherwise set to
985      * AV_NOPTS_VALUE by default.
986      */
987     int64_t first_dts;
988     int64_t cur_dts;
989     int64_t last_IP_pts;
990     int last_IP_duration;
991 
992     /**
993      * Number of packets to buffer for codec probing
994      */
995 //#define MAX_PROBE_PACKETS 2500
996     int probe_packets;
997 
998     /**
999      * Number of frames that have been demuxed during av_find_stream_info()
1000      */
1001     int codec_info_nb_frames;
1002 
1003     /* av_read_frame() support */
1004     AVStreamParseType need_parsing;
1005     AVCodecParserContext *parser;
1006 
1007     /**
1008      * last packet in packet_buffer for this stream when muxing.
1009      */
1010     AVPacketList *last_in_packet_buffer;
1011     AVProbeData probe_data;
1012 //#define MAX_REORDER_DELAY 16
1013     int64_t [MAX_REORDER_DELAY+1]pts_buffer;
1014 
1015     AVIndexEntry *index_entries; /**< Only used if the format does not
1016                                     support seeking natively. */
1017     int nb_index_entries;
1018     uint index_entries_allocated_size;
1019 
1020     /**
1021      * Real base framerate of the stream.
1022      * This is the lowest framerate with which all timestamps can be
1023      * represented accurately (it is the least common multiple of all
1024      * framerates in the stream). Note, this value is just a guess!
1025      * For example, if the time base is 1/90000 and all frames have either
1026      * approximately 3600 or 1800 timer ticks, then r_frame_rate will be 50/1.
1027      *
1028      * Code outside avformat should access this field using:
1029      * av_stream_get/set_r_frame_rate(stream)
1030      */
1031     AVRational r_frame_rate;
1032 
1033     /**
1034      * Stream Identifier
1035      * This is the MPEG-TS stream identifier +1
1036      * 0 means unknown
1037      */
1038     int stream_identifier;
1039 
1040     int64_t interleaver_chunk_size;
1041     int64_t interleaver_chunk_duration;
1042 
1043     /**
1044      * stream probing state
1045      * -1   -> probing finished
1046      *  0   -> no probing requested
1047      * rest -> perform probing with request_probe being the minimum score to accept.
1048      * NOT PART OF PUBLIC API
1049      */
1050     int request_probe;
1051     /**
1052      * Indicates that everything up to the next keyframe
1053      * should be discarded.
1054      */
1055     int skip_to_keyframe;
1056 
1057     /**
1058      * Number of samples to skip at the start of the frame decoded from the next packet.
1059      */
1060     int skip_samples;
1061 
1062     /**
1063      * If not 0, the number of samples that should be skipped from the start of
1064      * the stream (the samples are removed from packets with pts==0, which also
1065      * assumes negative timestamps do not happen).
1066      * Intended for use with formats such as mp3 with ad-hoc gapless audio
1067      * support.
1068      */
1069     int64_t start_skip_samples;
1070 
1071     /**
1072      * If not 0, the first audio sample that should be discarded from the stream.
1073      * This is broken by design (needs global sample count), but can't be
1074      * avoided for broken by design formats such as mp3 with ad-hoc gapless
1075      * audio support.
1076      */
1077     int64_t first_discard_sample;
1078 
1079     /**
1080      * The sample after last sample that is intended to be discarded after
1081      * first_discard_sample. Works on frame boundaries only. Used to prevent
1082      * early EOF if the gapless info is broken (considered concatenated mp3s).
1083      */
1084     int64_t last_discard_sample;
1085 
1086     /**
1087      * Number of internally decoded frames, used internally in libavformat, do not access
1088      * its lifetime differs from info which is why it is not in that structure.
1089      */
1090     int nb_decoded_frames;
1091 
1092     /**
1093      * Timestamp offset added to timestamps before muxing
1094      * NOT PART OF PUBLIC API
1095      */
1096     int64_t mux_ts_offset;
1097 
1098     /**
1099      * Internal data to check for wrapping of the time stamp
1100      */
1101     int64_t pts_wrap_reference;
1102 
1103     /**
1104      * Options for behavior, when a wrap is detected.
1105      *
1106      * Defined by AV_PTS_WRAP_ values.
1107      *
1108      * If correction is enabled, there are two possibilities:
1109      * If the first time stamp is near the wrap point, the wrap offset
1110      * will be subtracted, which will create negative time stamps.
1111      * Otherwise the offset will be added.
1112      */
1113     int pts_wrap_behavior;
1114 
1115     /**
1116      * Internal data to prevent doing update_initial_durations() twice
1117      */
1118     int update_initial_durations_done;
1119 
1120     /**
1121      * Internal data to generate dts from pts
1122      */
1123     int64_t [MAX_REORDER_DELAY+1]pts_reorder_error;
1124     uint8_t [MAX_REORDER_DELAY+1]pts_reorder_error_count;
1125 
1126     /**
1127      * Internal data to analyze DTS and detect faulty mpeg streams
1128      */
1129     int64_t last_dts_for_order_check;
1130     uint8_t dts_ordered;
1131     uint8_t dts_misordered;
1132 
1133     /**
1134      * Internal data to inject global side data
1135      */
1136     int inject_global_side_data;
1137 
1138     /**
1139      * String containing paris of key and values describing recommended encoder configuration.
1140      * Paris are separated by ','.
1141      * Keys are separated from values by '='.
1142      */
1143     char *recommended_encoder_configuration;
1144 
1145     /**
1146      * display aspect ratio (0 if unknown)
1147      * - encoding: unused
1148      * - decoding: Set by libavformat to calculate sample_aspect_ratio internally
1149      */
1150     AVRational display_aspect_ratio;
1151 
1152     FFFrac *priv_pts;
1153 
1154     /**
1155      * An opaque field for libavformat internal usage.
1156      * Must not be accessed in any way by callers.
1157      */
1158     AVStreamInternal *internal;
1159 
1160 }
1161 
1162 AVRational av_stream_get_r_frame_rate(const AVStream *s);
1163 void       av_stream_set_r_frame_rate(AVStream *s, AVRational r);
1164 AVCodecParserContext *av_stream_get_parser(const AVStream *s);
1165 char* av_stream_get_recommended_encoder_configuration(const AVStream *s);
1166 void  av_stream_set_recommended_encoder_configuration(AVStream *s, char *configuration);
1167 
1168 /**
1169  * Returns the pts of the last muxed packet + its duration
1170  *
1171  * the retuned value is undefined when used with a demuxer.
1172  */
1173 int64_t    av_stream_get_end_pts(const AVStream *st);
1174 
1175 enum AV_PROGRAM_RUNNING=1;
1176 
1177 /**
1178  * New fields can be added to the end with minor version bumps.
1179  * Removal, reordering and changes to existing fields require a major
1180  * version bump.
1181  * sizeof(AVProgram) must not be used outside libav*.
1182  */
1183 struct AVProgram {
1184     int            id;
1185     int            flags;
1186     AVDiscard discard;        ///< selects which program to discard and which to feed to the caller
1187     uint   *stream_index;
1188     uint   nb_stream_indexes;
1189     AVDictionary *metadata;
1190 
1191     int program_num;
1192     int pmt_pid;
1193     int pcr_pid;
1194 
1195     /*****************************************************************
1196      * All fields below this line are not part of the public API. They
1197      * may not be used outside of libavformat and can be changed and
1198      * removed at will.
1199      * New public fields should be added right above.
1200      *****************************************************************
1201      */
1202     int64_t start_time;
1203     int64_t end_time;
1204 
1205     int64_t pts_wrap_reference;    ///< reference dts for wrap detection
1206     int pts_wrap_behavior;         ///< behavior on wrap detection
1207 } 
1208 
1209 enum AVFMTCTX_NOHEADER    = 0x0001; /**< signal that no header is present
1210                                          (streams are added dynamically) */
1211 
1212 struct AVChapter {
1213     int id;                 ///< unique ID to identify the chapter
1214     AVRational time_base;   ///< time base in which the start/end timestamps are specified
1215     int64_t start, end;     ///< chapter start/end time in time_base units
1216     AVDictionary *metadata;
1217 }
1218 
1219 
1220 /**
1221  * Callback used by devices to communicate with application.
1222  */
1223 alias av_format_control_message = int function( AVFormatContext *s, int type,
1224                                          void *data, size_t data_size);
1225 
1226 alias AVOpenCallback = int function(AVFormatContext *s, AVIOContext **pb, const char *url, int flags,
1227                               const AVIOInterruptCB *int_cb, AVDictionary **options);
1228 
1229 /**
1230  * The duration of a video can be estimated through various ways, and this enum can be used
1231  * to know how the duration was estimated.
1232  */
1233 enum AVDurationEstimationMethod {
1234     AVFMT_DURATION_FROM_PTS,    ///< Duration accurately estimated from PTSes
1235     AVFMT_DURATION_FROM_STREAM, ///< Duration estimated from a stream with a known duration
1236     AVFMT_DURATION_FROM_BITRATE ///< Duration estimated from bitrate (less accurate)
1237 }
1238 
1239 struct AVFormatInternal;
1240 
1241 /**
1242  * Format I/O context.
1243  * New fields can be added to the end with minor version bumps.
1244  * Removal, reordering and changes to existing fields require a major
1245  * version bump.
1246  * sizeof(AVFormatContext) must not be used outside libav*, use
1247  * avformat_alloc_context() to create an AVFormatContext.
1248  */
1249 struct AVFormatContext {
1250     /**
1251      * A class for logging and @ref avoptions. Set by avformat_alloc_context().
1252      * Exports (de)muxer private options if they exist.
1253      */
1254     const AVClass *av_class;
1255 
1256     /**
1257      * The input container format.
1258      *
1259      * Demuxing only, set by avformat_open_input().
1260      */
1261     AVInputFormat *iformat;
1262 
1263     /**
1264      * The output container format.
1265      *
1266      * Muxing only, must be set by the caller before avformat_write_header().
1267      */
1268     AVOutputFormat *oformat;
1269 
1270     /**
1271      * Format private data. This is an AVOptions-enabled struct
1272      * if and only if iformat/oformat.priv_class is not NULL.
1273      *
1274      * - muxing: set by avformat_write_header()
1275      * - demuxing: set by avformat_open_input()
1276      */
1277     void *priv_data;
1278 
1279     /**
1280      * I/O context.
1281      *
1282      * - demuxing: either set by the user before avformat_open_input() (then
1283      *             the user must close it manually) or set by avformat_open_input().
1284      * - muxing: set by the user before avformat_write_header(). The caller must
1285      *           take care of closing / freeing the IO context.
1286      *
1287      * Do NOT set this field if AVFMT_NOFILE flag is set in
1288      * iformat/oformat.flags. In such a case, the (de)muxer will handle
1289      * I/O in some other way and this field will be NULL.
1290      */
1291     AVIOContext *pb;
1292 
1293     /* stream info */
1294     /**
1295      * Flags signalling stream properties. A combination of AVFMTCTX_*.
1296      * Set by libavformat.
1297      */
1298     int ctx_flags;
1299 
1300     /**
1301      * Number of elements in AVFormatContext.streams.
1302      *
1303      * Set by avformat_new_stream(), must not be modified by any other code.
1304      */
1305      uint nb_streams;
1306     /**
1307      * A list of all streams in the file. New streams are created with
1308      * avformat_new_stream().
1309      *
1310      * - demuxing: streams are created by libavformat in avformat_open_input().
1311      *             If AVFMTCTX_NOHEADER is set in ctx_flags, then new streams may also
1312      *             appear in av_read_frame().
1313      * - muxing: streams are created by the user before avformat_write_header().
1314      *
1315      * Freed by libavformat in avformat_free_context().
1316      */
1317     AVStream **streams;
1318 
1319     /**
1320      * input or output filename
1321      *
1322      * - demuxing: set by avformat_open_input()
1323      * - muxing: may be set by the caller before avformat_write_header()
1324      */
1325     char [1024]filename;
1326 
1327     /**
1328      * Position of the first frame of the component, in
1329      * AV_TIME_BASE fractional seconds. NEVER set this value directly:
1330      * It is deduced from the AVStream values.
1331      *
1332      * Demuxing only, set by libavformat.
1333      */
1334     int64_t start_time;
1335 
1336     /**
1337      * Duration of the stream, in AV_TIME_BASE fractional
1338      * seconds. Only set this value if you know none of the individual stream
1339      * durations and also do not set any of them. This is deduced from the
1340      * AVStream values if not set.
1341      *
1342      * Demuxing only, set by libavformat.
1343      */
1344     int64_t duration;
1345 
1346     /**
1347      * Total stream bitrate in bit/s, 0 if not
1348      * available. Never set it directly if the file_size and the
1349      * duration are known as FFmpeg can compute it automatically.
1350      */
1351     int64_t bit_rate;
1352 
1353     uint packet_size;
1354     int max_delay;
1355 
1356     /**
1357      * Flags modifying the (de)muxer behaviour. A combination of AVFMT_FLAG_*.
1358      * Set by the user before avformat_open_input() / avformat_write_header().
1359      */
1360     int flags;
1361 //#define AVFMT_FLAG_GENPTS       0x0001 ///< Generate missing pts even if it requires parsing future frames.
1362 //#define AVFMT_FLAG_IGNIDX       0x0002 ///< Ignore index.
1363 //#define AVFMT_FLAG_NONBLOCK     0x0004 ///< Do not block when reading packets from input.
1364 //#define AVFMT_FLAG_IGNDTS       0x0008 ///< Ignore DTS on frames that contain both DTS & PTS
1365 //#define AVFMT_FLAG_NOFILLIN     0x0010 ///< Do not infer any values from other values, just return what is stored in the container
1366 //#define AVFMT_FLAG_NOPARSE      0x0020 ///< Do not use AVParsers, you also must set AVFMT_FLAG_NOFILLIN as the fillin code works on frames and no parsing -> no frames. Also seeking to frames can not work if parsing to find frame boundaries has been disabled
1367 //#define AVFMT_FLAG_NOBUFFER     0x0040 ///< Do not buffer frames when possible
1368 //#define AVFMT_FLAG_CUSTOM_IO    0x0080 ///< The caller has supplied a custom AVIOContext, don't avio_close() it.
1369 //#define AVFMT_FLAG_DISCARD_CORRUPT  0x0100 ///< Discard frames marked corrupted
1370 //#define AVFMT_FLAG_FLUSH_PACKETS    0x0200 ///< Flush the AVIOContext every packet.
1371 /**
1372  * When muxing, try to avoid writing any random/volatile data to the output.
1373  * This includes any random IDs, real-time timestamps/dates, muxer version, etc.
1374  *
1375  * This flag is mainly intended for testing.
1376  */
1377 //#define AVFMT_FLAG_BITEXACT         0x0400
1378 //#define AVFMT_FLAG_MP4A_LATM    0x8000 ///< Enable RTP MP4A-LATM payload
1379 //#define AVFMT_FLAG_SORT_DTS    0x10000 ///< try to interleave outputted packets by dts (using this flag can slow demuxing down)
1380 //#define AVFMT_FLAG_PRIV_OPT    0x20000 ///< Enable use of private options by delaying codec open (this could be made default once all code is converted)
1381 //#define AVFMT_FLAG_KEEP_SIDE_DATA 0x40000 ///< Don't merge side data but keep it separate.
1382 
1383     /**
1384      * @deprecated deprecated in favor of probesize2
1385      */
1386     int64_t probesize;
1387 
1388     /**
1389      * Maximum duration (in AV_TIME_BASE units) of the data read
1390      * from input in avformat_find_stream_info().
1391      * Demuxing only, set by the caller before avformat_find_stream_info().
1392      * Can be set to 0 to let avformat choose using a heuristic.
1393      */
1394     int64_t max_analyze_duration;
1395 
1396     const uint8_t *key;
1397     int keylen;
1398 
1399     uint nb_programs;
1400     AVProgram **programs;
1401 
1402     /**
1403      * Forced video codec_id.
1404      * Demuxing: Set by user.
1405      */
1406     AVCodecID video_codec_id;
1407 
1408     /**
1409      * Forced audio codec_id.
1410      * Demuxing: Set by user.
1411      */
1412     AVCodecID audio_codec_id;
1413 
1414     /**
1415      * Forced subtitle codec_id.
1416      * Demuxing: Set by user.
1417      */
1418     AVCodecID subtitle_codec_id;
1419 
1420     /**
1421      * Maximum amount of memory in bytes to use for the index of each stream.
1422      * If the index exceeds this size, entries will be discarded as
1423      * needed to maintain a smaller size. This can lead to slower or less
1424      * accurate seeking (depends on demuxer).
1425      * Demuxers for which a full in-memory index is mandatory will ignore
1426      * this.
1427      * - muxing: unused
1428      * - demuxing: set by user
1429      */
1430     uint max_index_size;
1431 
1432     /**
1433      * Maximum amount of memory in bytes to use for buffering frames
1434      * obtained from realtime capture devices.
1435      */
1436     uint max_picture_buffer;
1437 
1438     /**
1439      * Number of chapters in AVChapter array.
1440      * When muxing, chapters are normally written in the file header,
1441      * so nb_chapters should normally be initialized before write_header
1442      * is called. Some muxers (e.g. mov and mkv) can also write chapters
1443      * in the trailer.  To write chapters in the trailer, nb_chapters
1444      * must be zero when write_header is called and non-zero when
1445      * write_trailer is called.
1446      * - muxing: set by user
1447      * - demuxing: set by libavformat
1448      */
1449     uint nb_chapters;
1450     AVChapter **chapters;
1451 
1452     /**
1453      * Metadata that applies to the whole file.
1454      *
1455      * - demuxing: set by libavformat in avformat_open_input()
1456      * - muxing: may be set by the caller before avformat_write_header()
1457      *
1458      * Freed by libavformat in avformat_free_context().
1459      */
1460     AVDictionary *metadata;
1461 
1462     /**
1463      * Start time of the stream in real world time, in microseconds
1464      * since the Unix epoch (00:00 1st January 1970). That is, pts=0 in the
1465      * stream was captured at this real world time.
1466      * - muxing: Set by the caller before avformat_write_header(). If set to
1467      *           either 0 or AV_NOPTS_VALUE, then the current wall-time will
1468      *           be used.
1469      * - demuxing: Set by libavformat. AV_NOPTS_VALUE if unknown. Note that
1470      *             the value may become known after some number of frames
1471      *             have been received.
1472      */
1473     int64_t start_time_realtime;
1474 
1475     /**
1476      * The number of frames used for determining the framerate in
1477      * avformat_find_stream_info().
1478      * Demuxing only, set by the caller before avformat_find_stream_info().
1479      */
1480     int fps_probe_size;
1481 
1482     /**
1483      * Error recognition; higher values will detect more errors but may
1484      * misdetect some more or less valid parts as errors.
1485      * Demuxing only, set by the caller before avformat_open_input().
1486      */
1487     int error_recognition;
1488 
1489     /**
1490      * Custom interrupt callbacks for the I/O layer.
1491      *
1492      * demuxing: set by the user before avformat_open_input().
1493      * muxing: set by the user before avformat_write_header()
1494      * (mainly useful for AVFMT_NOFILE formats). The callback
1495      * should also be passed to avio_open2() if it's used to
1496      * open the file.
1497      */
1498     AVIOInterruptCB interrupt_callback;
1499 
1500     /**
1501      * Flags to enable debugging.
1502      */
1503     int _debug;
1504 //#define FF_FDEBUG_TS        0x0001
1505 
1506     /**
1507      * Maximum buffering duration for interleaving.
1508      *
1509      * To ensure all the streams are interleaved correctly,
1510      * av_interleaved_write_frame() will wait until it has at least one packet
1511      * for each stream before actually writing any packets to the output file.
1512      * When some streams are "sparse" (i.e. there are large gaps between
1513      * successive packets), this can result in excessive buffering.
1514      *
1515      * This field specifies the maximum difference between the timestamps of the
1516      * first and the last packet in the muxing queue, above which libavformat
1517      * will output a packet regardless of whether it has queued a packet for all
1518      * the streams.
1519      *
1520      * Muxing only, set by the caller before avformat_write_header().
1521      */
1522     int64_t max_interleave_delta;
1523 
1524     /**
1525      * Allow non-standard and experimental extension
1526      * @see AVCodecContext.strict_std_compliance
1527      */
1528     int strict_std_compliance;
1529 
1530     /**
1531      * Flags for the user to detect events happening on the file. Flags must
1532      * be cleared by the user once the event has been handled.
1533      * A combination of AVFMT_EVENT_FLAG_*.
1534      */
1535     int event_flags;
1536 //#define AVFMT_EVENT_FLAG_METADATA_UPDATED 0x0001 ///< The call resulted in updated metadata.
1537 
1538     /**
1539      * Maximum number of packets to read while waiting for the first timestamp.
1540      * Decoding only.
1541      */
1542     int max_ts_probe;
1543 
1544     /**
1545      * Avoid negative timestamps during muxing.
1546      * Any value of the AVFMT_AVOID_NEG_TS_* constants.
1547      * Note, this only works when using av_interleaved_write_frame. (interleave_packet_per_dts is in use)
1548      * - muxing: Set by user
1549      * - demuxing: unused
1550      */
1551     int avoid_negative_ts;
1552 //#define AVFMT_AVOID_NEG_TS_AUTO             -1 ///< Enabled when required by target format
1553 //#define AVFMT_AVOID_NEG_TS_MAKE_NON_NEGATIVE 1 ///< Shift timestamps so they are non negative
1554 //#define AVFMT_AVOID_NEG_TS_MAKE_ZERO         2 ///< Shift timestamps so that they start at 0
1555 
1556     /**
1557      * Transport stream id.
1558      * This will be moved into demuxer private options. Thus no API/ABI compatibility
1559      */
1560     int ts_id;
1561 
1562     /**
1563      * Audio preload in microseconds.
1564      * Note, not all formats support this and unpredictable things may happen if it is used when not supported.
1565      * - encoding: Set by user via AVOptions (NO direct access)
1566      * - decoding: unused
1567      */
1568     int audio_preload;
1569 
1570     /**
1571      * Max chunk time in microseconds.
1572      * Note, not all formats support this and unpredictable things may happen if it is used when not supported.
1573      * - encoding: Set by user via AVOptions (NO direct access)
1574      * - decoding: unused
1575      */
1576     int max_chunk_duration;
1577 
1578     /**
1579      * Max chunk size in bytes
1580      * Note, not all formats support this and unpredictable things may happen if it is used when not supported.
1581      * - encoding: Set by user via AVOptions (NO direct access)
1582      * - decoding: unused
1583      */
1584     int max_chunk_size;
1585 
1586     /**
1587      * forces the use of wallclock timestamps as pts/dts of packets
1588      * This has undefined results in the presence of B frames.
1589      * - encoding: unused
1590      * - decoding: Set by user via AVOptions (NO direct access)
1591      */
1592     int use_wallclock_as_timestamps;
1593 
1594     /**
1595      * avio flags, used to force AVIO_FLAG_DIRECT.
1596      * - encoding: unused
1597      * - decoding: Set by user via AVOptions (NO direct access)
1598      */
1599     int avio_flags;
1600 
1601     /**
1602      * The duration field can be estimated through various ways, and this field can be used
1603      * to know how the duration was estimated.
1604      * - encoding: unused
1605      * - decoding: Read by user via AVOptions (NO direct access)
1606      */
1607     AVDurationEstimationMethod duration_estimation_method;
1608 
1609     /**
1610      * Skip initial bytes when opening stream
1611      * - encoding: unused
1612      * - decoding: Set by user via AVOptions (NO direct access)
1613      */
1614     int64_t skip_initial_bytes;
1615 
1616     /**
1617      * Correct single timestamp overflows
1618      * - encoding: unused
1619      * - decoding: Set by user via AVOPtions (NO direct access)
1620      */
1621     uint correct_ts_overflow;
1622 
1623     /**
1624      * Force seeking to any (also non key) frames.
1625      * - encoding: unused
1626      * - decoding: Set by user via AVOPtions (NO direct access)
1627      */
1628     int seek2any;
1629 
1630     /**
1631      * Flush the I/O context after each packet.
1632      * - encoding: Set by user via AVOptions (NO direct access)
1633      * - decoding: unused
1634      */
1635     int flush_packets;
1636 
1637     /**
1638      * format probing score.
1639      * The maximal score is AVPROBE_SCORE_MAX, its set when the demuxer probes
1640      * the format.
1641      * - encoding: unused
1642      * - decoding: set by avformat, read by user via av_format_get_probe_score() (NO direct access)
1643      */
1644     int probe_score;
1645 
1646     /**
1647      * number of bytes to read maximally to identify format.
1648      * - encoding: unused
1649      * - decoding: set by user through AVOPtions (NO direct access)
1650      */
1651     int format_probesize;
1652 
1653     /**
1654      * ',' separated list of allowed decoders.
1655      * If NULL then all are allowed
1656      * - encoding: unused
1657      * - decoding: set by user through AVOptions (NO direct access)
1658      */
1659     char *codec_whitelist;
1660 
1661     /**
1662      * ',' separated list of allowed demuxers.
1663      * If NULL then all are allowed
1664      * - encoding: unused
1665      * - decoding: set by user through AVOptions (NO direct access)
1666      */
1667     char *format_whitelist;
1668 
1669     /**
1670      * An opaque field for libavformat internal usage.
1671      * Must not be accessed in any way by callers.
1672      */
1673     AVFormatInternal *internal;
1674 
1675     /**
1676      * IO repositioned flag.
1677      * This is set by avformat when the underlaying IO context read pointer
1678      * is repositioned, for example when doing byte based seeking.
1679      * Demuxers can use the flag to detect such changes.
1680      */
1681     int io_repositioned;
1682 
1683     /**
1684      * Forced video codec.
1685      * This allows forcing a specific decoder, even when there are multiple with
1686      * the same codec_id.
1687      * Demuxing: Set by user via av_format_set_video_codec (NO direct access).
1688      */
1689     AVCodec *video_codec;
1690 
1691     /**
1692      * Forced audio codec.
1693      * This allows forcing a specific decoder, even when there are multiple with
1694      * the same codec_id.
1695      * Demuxing: Set by user via av_format_set_audio_codec (NO direct access).
1696      */
1697     AVCodec *audio_codec;
1698 
1699     /**
1700      * Forced subtitle codec.
1701      * This allows forcing a specific decoder, even when there are multiple with
1702      * the same codec_id.
1703      * Demuxing: Set by user via av_format_set_subtitle_codec (NO direct access).
1704      */
1705     AVCodec *subtitle_codec;
1706 
1707     /**
1708      * Forced data codec.
1709      * This allows forcing a specific decoder, even when there are multiple with
1710      * the same codec_id.
1711      * Demuxing: Set by user via av_format_set_data_codec (NO direct access).
1712      */
1713     AVCodec *data_codec;
1714 
1715     /**
1716      * Number of bytes to be written as padding in a metadata header.
1717      * Demuxing: Unused.
1718      * Muxing: Set by user via av_format_set_metadata_header_padding.
1719      */
1720     int metadata_header_padding;
1721 
1722     /**
1723      * User data.
1724      * This is a place for some private data of the user.
1725      * Mostly usable with control_message_cb or any future callbacks in device's context.
1726      */
1727     void *opaque;
1728 
1729     /**
1730      * Callback used by devices to communicate with application.
1731      */
1732     av_format_control_message control_message_cb;
1733 
1734     /**
1735      * Output timestamp offset, in microseconds.
1736      * Muxing: set by user via AVOptions (NO direct access)
1737      */
1738     int64_t output_ts_offset;
1739 
1740     /**
1741      * dump format separator.
1742      * can be ", " or "\n      " or anything else
1743      * Code outside libavformat should access this field using AVOptions
1744      * (NO direct access).
1745      * - muxing: Set by user.
1746      * - demuxing: Set by user.
1747      */
1748     uint8_t *dump_separator;
1749 
1750     /**
1751      * Forced Data codec_id.
1752      * Demuxing: Set by user.
1753      */
1754     AVCodecID data_codec_id;
1755 
1756 static if(FF_API_OLD_OPEN_CALLBACKS){
1757     /**
1758      * Called to open further IO contexts when needed for demuxing.
1759      *
1760      * This can be set by the user application to perform security checks on
1761      * the URLs before opening them.
1762      * The function should behave like avio_open2(), AVFormatContext is provided
1763      * as contextual information and to reach AVFormatContext.opaque.
1764      *
1765      * If NULL then some simple checks are used together with avio_open2().
1766      *
1767      * Must not be accessed directly from outside avformat.
1768      * @See av_format_set_open_cb()
1769      *
1770      * Demuxing: Set by user.
1771      *
1772      * @deprecated Use io_open and io_close.
1773      */
1774     deprecated
1775         int function(AVFormatContext *s, AVIOContext **p, const char *url, int flags, const AVIOInterruptCB *int_cb,
1776                      AVDictionary **options) open_cb;
1777 }
1778 
1779     /**
1780      * ',' separated list of allowed protocols.
1781      * - encoding: unused
1782      * - decoding: set by user through AVOptions (NO direct access)
1783      */
1784     char *protocol_whitelist;
1785 
1786     /*
1787      * A callback for opening new IO streams.
1788      *
1789      * Certain muxers or demuxers (e.g. for various playlist-based formats) need
1790      * to open additional files during muxing or demuxing. This callback allows
1791      * the caller to provide custom IO in such cases.
1792      *
1793      * @param s the format context
1794      * @param pb on success, the newly opened IO context should be returned here
1795      * @param url the url to open
1796      * @param flags a combination of AVIO_FLAG_*
1797      * @param options a dictionary of additional options, with the same
1798      *                semantics as in avio_open2()
1799      * @return 0 on success, a negative AVERROR code on failure
1800      *
1801      * @note Certain muxers and demuxers do nesting, i.e. they open one or more
1802      * additional internal format contexts. Thus the AVFormatContext pointer
1803      * passed to this callback may be different from the one facing the caller.
1804      * It will, however, have the same 'opaque' field.
1805      */
1806     int function(AVFormatContext *s, AVIOContext **pb, const char *url, int flags, AVDictionary **options) io_open;
1807 
1808     /**
1809      * A callback for closing the streams opened with AVFormatContext.io_open().
1810      */
1811     void function(AVFormatContext *s, AVIOContext *pb) io_close;
1812 }
1813 
1814 int av_format_get_probe_score(const AVFormatContext *s);
1815 AVCodec * av_format_get_video_codec(const AVFormatContext *s);
1816 void      av_format_set_video_codec(AVFormatContext *s, AVCodec *c);
1817 AVCodec * av_format_get_audio_codec(const AVFormatContext *s);
1818 void      av_format_set_audio_codec(AVFormatContext *s, AVCodec *c);
1819 AVCodec * av_format_get_subtitle_codec(const AVFormatContext *s);
1820 void      av_format_set_subtitle_codec(AVFormatContext *s, AVCodec *c);
1821 AVCodec * av_format_get_data_codec(const AVFormatContext *s);
1822 void      av_format_set_data_codec(AVFormatContext *s, AVCodec *c);
1823 int       av_format_get_metadata_header_padding(const AVFormatContext *s);
1824 void      av_format_set_metadata_header_padding(AVFormatContext *s, int c);
1825 void *    av_format_get_opaque(const AVFormatContext *s);
1826 void      av_format_set_opaque(AVFormatContext *s, void *opaque);
1827 av_format_control_message av_format_get_control_message_cb(const AVFormatContext *s);
1828 void      av_format_set_control_message_cb(AVFormatContext *s, av_format_control_message callback);
1829 static if(FF_API_OLD_OPEN_CALLBACKS){
1830     deprecated AVOpenCallback av_format_get_open_cb(const AVFormatContext *s);
1831     deprecated void av_format_set_open_cb(AVFormatContext *s, AVOpenCallback callback);
1832 }
1833 
1834 /**
1835  * This function will cause global side data to be injected in the next packet
1836  * of each stream as well as after any subsequent seek.
1837  */
1838 void av_format_inject_global_side_data(AVFormatContext *s);
1839 
1840 /**
1841  * Returns the method used to set ctx->duration.
1842  *
1843  * @return AVFMT_DURATION_FROM_PTS, AVFMT_DURATION_FROM_STREAM, or AVFMT_DURATION_FROM_BITRATE.
1844  */
1845 AVDurationEstimationMethod av_fmt_ctx_get_duration_estimation_method(const AVFormatContext* ctx);
1846 
1847 
1848 struct AVPacketList {
1849     AVPacket pkt;
1850     AVPacketList *next;
1851 }
1852 
1853 /**
1854  * @defgroup lavf_core Core functions
1855  * @ingroup libavf
1856  *
1857  * Functions for querying libavformat capabilities, allocating core structures,
1858  * etc.
1859  * @{
1860  */
1861 
1862 /**
1863  * Return the LIBAVFORMAT_VERSION_INT constant.
1864  */
1865 uint avformat_version();
1866 
1867 /**
1868  * Return the libavformat build-time configuration.
1869  */
1870 char *avformat_configuration();
1871 
1872 /**
1873  * Return the libavformat license.
1874  */
1875 char *avformat_license();
1876 
1877 /**
1878  * Initialize libavformat and register all the muxers, demuxers and
1879  * protocols. If you do not call this function, then you can select
1880  * exactly which formats you want to support.
1881  *
1882  * @see av_register_input_format()
1883  * @see av_register_output_format()
1884  */
1885 void av_register_all();
1886 
1887 void av_register_input_format(AVInputFormat *format);
1888 void av_register_output_format(AVOutputFormat *format);
1889 
1890 /**
1891  * Do global initialization of network components. This is optional,
1892  * but recommended, since it avoids the overhead of implicitly
1893  * doing the setup for each session.
1894  *
1895  * Calling this function will become mandatory if using network
1896  * protocols at some major version bump.
1897  */
1898 int avformat_network_init();
1899 
1900 /**
1901  * Undo the initialization done by avformat_network_init.
1902  */
1903 int avformat_network_deinit();
1904 
1905 /**
1906  * If f is NULL, returns the first registered input format,
1907  * if f is non-NULL, returns the next registered input format after f
1908  * or NULL if f is the last one.
1909  */
1910 AVInputFormat  *av_iformat_next(AVInputFormat  *f);
1911 
1912 /**
1913  * If f is NULL, returns the first registered output format,
1914  * if f is non-NULL, returns the next registered output format after f
1915  * or NULL if f is the last one.
1916  */
1917 AVOutputFormat *av_oformat_next(AVOutputFormat *f);
1918 
1919 /**
1920  * Allocate an AVFormatContext.
1921  * avformat_free_context() can be used to free the context and everything
1922  * allocated by the framework within it.
1923  */
1924 AVFormatContext *avformat_alloc_context();
1925 
1926 /**
1927  * Free an AVFormatContext and all its streams.
1928  * @param s context to free
1929  */
1930 void avformat_free_context(AVFormatContext *s);
1931 
1932 /**
1933  * Get the AVClass for AVFormatContext. It can be used in combination with
1934  * AV_OPT_SEARCH_FAKE_OBJ for examining options.
1935  *
1936  * @see av_opt_find().
1937  */
1938 AVClass *avformat_get_class();
1939 
1940 /**
1941  * Add a new stream to a media file.
1942  *
1943  * When demuxing, it is called by the demuxer in read_header(). If the
1944  * flag AVFMTCTX_NOHEADER is set in s.ctx_flags, then it may also
1945  * be called in read_packet().
1946  *
1947  * When muxing, should be called by the user before avformat_write_header().
1948  *
1949  * User is required to call avcodec_close() and avformat_free_context() to
1950  * clean up the allocation by avformat_new_stream().
1951  *
1952  * @param s media file handle
1953  * @param c If non-NULL, the AVCodecContext corresponding to the new stream
1954  * will be initialized to use this codec. This is needed for e.g. codec-specific
1955  * defaults to be set, so codec should be provided if it is known.
1956  *
1957  * @return newly created stream or NULL on error.
1958  */
1959 AVStream *avformat_new_stream(AVFormatContext *s, const AVCodec *c);
1960 
1961 /**
1962  * Allocate new information from stream.
1963  *
1964  * @param stream stream
1965  * @param type desired side information type
1966  * @param size side information size
1967  * @return pointer to fresh allocated data or NULL otherwise
1968  */
1969 uint8_t *av_stream_new_side_data(AVStream *stream,
1970                                  AVPacketSideDataType type, int size);
1971 
1972 /**
1973  * Get side information from stream.
1974  *
1975  * @param stream stream
1976  * @param type desired side information type
1977  * @param size pointer for side information size to store (optional)
1978  * @return pointer to data if present or NULL otherwise
1979  */
1980 uint8_t *av_stream_get_side_data(AVStream *stream,
1981                                  AVPacketSideDataType type, int *size);
1982 
1983 AVProgram *av_new_program(AVFormatContext *s, int id);
1984 
1985 /**
1986  * @}
1987  */
1988 
1989 
1990 /**
1991  * Allocate an AVFormatContext for an output format.
1992  * avformat_free_context() can be used to free the context and
1993  * everything allocated by the framework within it.
1994  *
1995  * @param *ctx is set to the created format context, or to NULL in
1996  * case of failure
1997  * @param oformat format to use for allocating the context, if NULL
1998  * format_name and filename are used instead
1999  * @param format_name the name of output format to use for allocating the
2000  * context, if NULL filename is used instead
2001  * @param filename the name of the filename to use for allocating the
2002  * context, may be NULL
2003  * @return >= 0 in case of success, a negative AVERROR code in case of
2004  * failure
2005  */
2006 int avformat_alloc_output_context2(AVFormatContext **ctx, AVOutputFormat *oformat,
2007                                    const char *format_name, const char *filename);
2008 
2009 /**
2010  * @addtogroup lavf_decoding
2011  * @{
2012  */
2013 
2014 /**
2015  * Find AVInputFormat based on the short name of the input format.
2016  */
2017 AVInputFormat *av_find_input_format(const char *short_name);
2018 
2019 /**
2020  * Guess the file format.
2021  *
2022  * @param pd        data to be probed
2023  * @param is_opened Whether the file is already opened; determines whether
2024  *                  demuxers with or without AVFMT_NOFILE are probed.
2025  */
2026 AVInputFormat *av_probe_input_format(AVProbeData *pd, int is_opened);
2027 
2028 /**
2029  * Guess the file format.
2030  *
2031  * @param pd        data to be probed
2032  * @param is_opened Whether the file is already opened; determines whether
2033  *                  demuxers with or without AVFMT_NOFILE are probed.
2034  * @param score_max A probe score larger that this is required to accept a
2035  *                  detection, the variable is set to the actual detection
2036  *                  score afterwards.
2037  *                  If the score is <= AVPROBE_SCORE_MAX / 4 it is recommended
2038  *                  to retry with a larger probe buffer.
2039  */
2040 AVInputFormat *av_probe_input_format2(AVProbeData *pd, int is_opened, int *score_max);
2041 
2042 /**
2043  * Guess the file format.
2044  *
2045  * @param is_opened Whether the file is already opened; determines whether
2046  *                  demuxers with or without AVFMT_NOFILE are probed.
2047  * @param score_ret The score of the best detection.
2048  */
2049 AVInputFormat *av_probe_input_format3(AVProbeData *pd, int is_opened, int *score_ret);
2050 
2051 /**
2052  * Probe a bytestream to determine the input format. Each time a probe returns
2053  * with a score that is too low, the probe buffer size is increased and another
2054  * attempt is made. When the maximum probe size is reached, the input format
2055  * with the highest score is returned.
2056  *
2057  * @param pb the bytestream to probe
2058  * @param fmt the input format is put here
2059  * @param filename the filename of the stream
2060  * @param logctx the log context
2061  * @param offset the offset within the bytestream to probe from
2062  * @param max_probe_size the maximum probe buffer size (zero for default)
2063  * @return the score in case of success, a negative value corresponding to an
2064  *         the maximal score is AVPROBE_SCORE_MAX
2065  * AVERROR code otherwise
2066  */
2067 int av_probe_input_buffer2(AVIOContext *pb, AVInputFormat **fmt,
2068                            const char *filename, void *logctx,
2069                            uint offset, uint max_probe_size);
2070 
2071 /**
2072  * Like av_probe_input_buffer2() but returns 0 on success
2073  */
2074 int av_probe_input_buffer(AVIOContext *pb, AVInputFormat **fmt,
2075                           const char *filename, void *logctx,
2076                           uint offset, uint max_probe_size);
2077 
2078 /**
2079  * Open an input stream and read the header. The codecs are not opened.
2080  * The stream must be closed with avformat_close_input().
2081  *
2082  * @param ps Pointer to user-supplied AVFormatContext (allocated by avformat_alloc_context).
2083  *           May be a pointer to NULL, in which case an AVFormatContext is allocated by this
2084  *           function and written into ps.
2085  *           Note that a user-supplied AVFormatContext will be freed on failure.
2086  * @param filename Name of the stream to open.
2087  * @param fmt If non-NULL, this parameter forces a specific input format.
2088  *            Otherwise the format is autodetected.
2089  * @param options  A dictionary filled with AVFormatContext and demuxer-private options.
2090  *                 On return this parameter will be destroyed and replaced with a dict containing
2091  *                 options that were not found. May be NULL.
2092  *
2093  * @return 0 on success, a negative AVERROR on failure.
2094  *
2095  * @note If you want to use custom IO, preallocate the format context and set its pb field.
2096  */
2097 int avformat_open_input(AVFormatContext **ps, const char *filename, AVInputFormat *fmt, AVDictionary **options);
2098 
2099 deprecated
2100 int av_demuxer_open(AVFormatContext *ic);
2101 
2102 /**
2103  * Read packets of a media file to get stream information. This
2104  * is useful for file formats with no headers such as MPEG. This
2105  * function also computes the real framerate in case of MPEG-2 repeat
2106  * frame mode.
2107  * The logical file position is not changed by this function;
2108  * examined packets may be buffered for later processing.
2109  *
2110  * @param ic media file handle
2111  * @param options  If non-NULL, an ic.nb_streams long array of pointers to
2112  *                 dictionaries, where i-th member contains options for
2113  *                 codec corresponding to i-th stream.
2114  *                 On return each dictionary will be filled with options that were not found.
2115  * @return >=0 if OK, AVERROR_xxx on error
2116  *
2117  * @note this function isn't guaranteed to open all the codecs, so
2118  *       options being non-empty at return is a perfectly normal behavior.
2119  *
2120  * @todo Let the user decide somehow what information is needed so that
2121  *       we do not waste time getting stuff the user does not need.
2122  */
2123 int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options);
2124 
2125 /**
2126  * Find the programs which belong to a given stream.
2127  *
2128  * @param ic    media file handle
2129  * @param last  the last found program, the search will start after this
2130  *              program, or from the beginning if it is NULL
2131  * @param s     stream index
2132  * @return the next program which belongs to s, NULL if no program is found or
2133  *         the last program is not among the programs of ic.
2134  */
2135 AVProgram *av_find_program_from_stream(AVFormatContext *ic, AVProgram *last, int s);
2136 
2137 void av_program_add_stream_index(AVFormatContext *ac, int progid, uint idx);
2138 
2139 /**
2140  * Find the "best" stream in the file.
2141  * The best stream is determined according to various heuristics as the most
2142  * likely to be what the user expects.
2143  * If the decoder parameter is non-NULL, av_find_best_stream will find the
2144  * default decoder for the stream's codec; streams for which no decoder can
2145  * be found are ignored.
2146  *
2147  * @param ic                media file handle
2148  * @param type              stream type: video, audio, subtitles, etc.
2149  * @param wanted_stream_nb  user-requested stream number,
2150  *                          or -1 for automatic selection
2151  * @param related_stream    try to find a stream related (eg. in the same
2152  *                          program) to this one, or -1 if none
2153  * @param decoder_ret       if non-NULL, returns the decoder for the
2154  *                          selected stream
2155  * @param flags             flags; none are currently defined
2156  * @return  the non-negative stream number in case of success,
2157  *          AVERROR_STREAM_NOT_FOUND if no stream with the requested type
2158  *          could be found,
2159  *          AVERROR_DECODER_NOT_FOUND if streams were found but no decoder
2160  * @note  If av_find_best_stream returns successfully and decoder_ret is not
2161  *        NULL, then *decoder_ret is guaranteed to be set to a valid AVCodec.
2162  */
2163 int av_find_best_stream(AVFormatContext *ic,
2164                         AVMediaType media_type,
2165                         int wanted_stream_nb,
2166                         int related_stream,
2167                         AVCodec **decoder_ret,
2168                         int flags);
2169 
2170 /**
2171  * Return the next frame of a stream.
2172  * This function returns what is stored in the file, and does not validate
2173  * that what is there are valid frames for the decoder. It will split what is
2174  * stored in the file into frames and return one for each call. It will not
2175  * omit invalid data between valid frames so as to give the decoder the maximum
2176  * information possible for decoding.
2177  *
2178  * If pkt->buf is NULL, then the packet is valid until the next
2179  * av_read_frame() or until avformat_close_input(). Otherwise the packet
2180  * is valid indefinitely. In both cases the packet must be freed with
2181  * av_free_packet when it is no longer needed. For video, the packet contains
2182  * exactly one frame. For audio, it contains an integer number of frames if each
2183  * frame has a known fixed size (e.g. PCM or ADPCM data). If the audio frames
2184  * have a variable size (e.g. MPEG audio), then it contains one frame.
2185  *
2186  * pkt->pts, pkt->dts and pkt->duration are always set to correct
2187  * values in AVStream.time_base units (and guessed if the format cannot
2188  * provide them). pkt->pts can be AV_NOPTS_VALUE if the video format
2189  * has B-frames, so it is better to rely on pkt->dts if you do not
2190  * decompress the payload.
2191  *
2192  * @return 0 if OK, < 0 on error or end of file
2193  */
2194 int av_read_frame(AVFormatContext *s, AVPacket *pkt);
2195 
2196 /**
2197  * Seek to the keyframe at timestamp.
2198  * 'timestamp' in 'stream_index'.
2199  *
2200  * @param s media file handle
2201  * @param stream_index If stream_index is (-1), a default
2202  * stream is selected, and timestamp is automatically converted
2203  * from AV_TIME_BASE units to the stream specific time_base.
2204  * @param timestamp Timestamp in AVStream.time_base units
2205  *        or, if no stream is specified, in AV_TIME_BASE units.
2206  * @param flags flags which select direction and seeking mode
2207  * @return >= 0 on success
2208  */
2209 int av_seek_frame(AVFormatContext *s, int stream_index, int64_t timestamp,
2210                   int flags);
2211 
2212 /**
2213  * Seek to timestamp ts.
2214  * Seeking will be done so that the point from which all active streams
2215  * can be presented successfully will be closest to ts and within min/max_ts.
2216  * Active streams are all streams that have AVStream.discard < AVDISCARD_ALL.
2217  *
2218  * If flags contain AVSEEK_FLAG_BYTE, then all timestamps are in bytes and
2219  * are the file position (this may not be supported by all demuxers).
2220  * If flags contain AVSEEK_FLAG_FRAME, then all timestamps are in frames
2221  * in the stream with stream_index (this may not be supported by all demuxers).
2222  * Otherwise all timestamps are in units of the stream selected by stream_index
2223  * or if stream_index is -1, in AV_TIME_BASE units.
2224  * If flags contain AVSEEK_FLAG_ANY, then non-keyframes are treated as
2225  * keyframes (this may not be supported by all demuxers).
2226  * If flags contain AVSEEK_FLAG_BACKWARD, it is ignored.
2227  *
2228  * @param s media file handle
2229  * @param stream_index index of the stream which is used as time base reference
2230  * @param min_ts smallest acceptable timestamp
2231  * @param ts target timestamp
2232  * @param max_ts largest acceptable timestamp
2233  * @param flags flags
2234  * @return >=0 on success, error code otherwise
2235  *
2236  * @note This is part of the new seek API which is still under construction.
2237  *       Thus do not use this yet. It may change at any time, do not expect
2238  *       ABI compatibility yet!
2239  */
2240 int avformat_seek_file(AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags);
2241 
2242 /**
2243  * Discard all internally buffered data. This can be useful when dealing with
2244  * discontinuities in the byte stream. Generally works only with formats that
2245  * can resync. This includes headerless formats like MPEG-TS/TS but should also
2246  * work with NUT, Ogg and in a limited way AVI for example.
2247  *
2248  * The set of streams, the detected duration, stream parameters and codecs do
2249  * not change when calling this function. If you want a complete reset, it's
2250  * better to open a new AVFormatContext.
2251  *
2252  * This does not flush the AVIOContext (s->pb). If necessary, call
2253  * avio_flush(s->pb) before calling this function.
2254  *
2255  * @param s media file handle
2256  * @return >=0 on success, error code otherwise
2257  */
2258 int avformat_flush(AVFormatContext *s);
2259 
2260 /**
2261  * Start playing a network-based stream (e.g. RTSP stream) at the
2262  * current position.
2263  */
2264 int av_read_play(AVFormatContext *s);
2265 
2266 /**
2267  * Pause a network-based stream (e.g. RTSP stream).
2268  *
2269  * Use av_read_play() to resume it.
2270  */
2271 int av_read_pause(AVFormatContext *s);
2272 
2273 /**
2274  * Close an opened input AVFormatContext. Free it and all its contents
2275  * and set *s to NULL.
2276  */
2277 void avformat_close_input(AVFormatContext **s);
2278 /**
2279  * @}
2280  */
2281 
2282 enum AVSEEK_FLAG_BACKWARD = 1; ///< seek backward
2283 enum AVSEEK_FLAG_BYTE    = 2; ///< seeking based on position in bytes
2284 enum AVSEEK_FLAG_ANY     = 4; ///< seek to any frame, even non-keyframes
2285 enum AVSEEK_FLAG_FRAME   = 8; ///< seeking based on frame number
2286 
2287 /**
2288  * @addtogroup lavf_encoding
2289  * @{
2290  */
2291 /**
2292  * Allocate the stream private data and write the stream header to
2293  * an output media file.
2294  *
2295  * @param s Media file handle, must be allocated with avformat_alloc_context().
2296  *          Its oformat field must be set to the desired output format;
2297  *          Its pb field must be set to an already opened AVIOContext.
2298  * @param options  An AVDictionary filled with AVFormatContext and muxer-private options.
2299  *                 On return this parameter will be destroyed and replaced with a dict containing
2300  *                 options that were not found. May be NULL.
2301  *
2302  * @return 0 on success, negative AVERROR on failure.
2303  *
2304  * @see av_opt_find, av_dict_set, avio_open, av_oformat_next.
2305  */
2306 //av_warn_unused_result
2307 int avformat_write_header(AVFormatContext *s, AVDictionary **options);
2308 
2309 /**
2310  * Write a packet to an output media file.
2311  *
2312  * This function passes the packet directly to the muxer, without any buffering
2313  * or reordering. The caller is responsible for correctly interleaving the
2314  * packets if the format requires it. Callers that want libavformat to handle
2315  * the interleaving should call av_interleaved_write_frame() instead of this
2316  * function.
2317  *
2318  * @param s media file handle
2319  * @param pkt The packet containing the data to be written. Note that unlike
2320  *            av_interleaved_write_frame(), this function does not take
2321  *            ownership of the packet passed to it (though some muxers may make
2322  *            an internal reference to the input packet).
2323  *            <br>
2324  *            This parameter can be NULL (at any time, not just at the end), in
2325  *            order to immediately flush data buffered within the muxer, for
2326  *            muxers that buffer up data internally before writing it to the
2327  *            output.
2328  *            <br>
2329  *            Packet's @ref AVPacket.stream_index "stream_index" field must be
2330  *            set to the index of the corresponding stream in @ref
2331  *            AVFormatContext.streams "s->streams".
2332  *            <br>
2333  *            The timestamps (@ref AVPacket.pts "pts", @ref AVPacket.dts "dts")
2334  *            must be set to correct values in the stream's timebase (unless the
2335  *            output format is flagged with the AVFMT_NOTIMESTAMPS flag, then
2336  *            they can be set to AV_NOPTS_VALUE).
2337  *            The dts for subsequent packets passed to this function must be strictly
2338  *            increasing when compared in their respective timebases (unless the
2339  *            output format is flagged with the AVFMT_TS_NONSTRICT, then they
2340  *            merely have to be nondecreasing).  @ref AVPacket.duration
2341  *            "duration") should also be set if known.
2342  * @return < 0 on error, = 0 if OK, 1 if flushed and there is no more data to flush
2343  *
2344  * @see av_interleaved_write_frame()
2345  */
2346 int av_write_frame(AVFormatContext *s, AVPacket *pkt);
2347 
2348 /**
2349  * Write a packet to an output media file ensuring correct interleaving.
2350  *
2351  * This function will buffer the packets internally as needed to make sure the
2352  * packets in the output file are properly interleaved in the order of
2353  * increasing dts. Callers doing their own interleaving should call
2354  * av_write_frame() instead of this function.
2355  *
2356  * @param s media file handle
2357  * @param pkt The packet containing the data to be written.
2358  *            <br>
2359  *            If the packet is reference-counted, this function will take
2360  *            ownership of this reference and unreference it later when it sees
2361  *            fit.
2362  *            The caller must not access the data through this reference after
2363  *            this function returns. If the packet is not reference-counted,
2364  *            libavformat will make a copy.
2365  *            <br>
2366  *            This parameter can be NULL (at any time, not just at the end), to
2367  *            flush the interleaving queues.
2368  *            <br>
2369  *            Packet's @ref AVPacket.stream_index "stream_index" field must be
2370  *            set to the index of the corresponding stream in @ref
2371  *            AVFormatContext.streams "s->streams".
2372  *            <br>
2373  *            The timestamps (@ref AVPacket.pts "pts", @ref AVPacket.dts "dts")
2374  *            must be set to correct values in the stream's timebase (unless the
2375  *            output format is flagged with the AVFMT_NOTIMESTAMPS flag, then
2376  *            they can be set to AV_NOPTS_VALUE).
2377  *            The dts for subsequent packets in one stream must be strictly
2378  *            increasing (unless the output format is flagged with the
2379  *            AVFMT_TS_NONSTRICT, then they merely have to be nondecreasing).
2380  *            @ref AVPacket.duration "duration") should also be set if known.
2381  *
2382  * @return 0 on success, a negative AVERROR on error. Libavformat will always
2383  *         take care of freeing the packet, even if this function fails.
2384  *
2385  * @see av_write_frame(), AVFormatContext.max_interleave_delta
2386  */
2387 int av_interleaved_write_frame(AVFormatContext *s, AVPacket *pkt);
2388 
2389 /**
2390  * Write a uncoded frame to an output media file.
2391  *
2392  * The frame must be correctly interleaved according to the container
2393  * specification; if not, then av_interleaved_write_frame() must be used.
2394  *
2395  * See av_interleaved_write_frame() for details.
2396  */
2397 int av_write_uncoded_frame(AVFormatContext *s, int stream_index,
2398                            AVFrame *frame);
2399 
2400 /**
2401  * Write a uncoded frame to an output media file.
2402  *
2403  * If the muxer supports it, this function allows to write an AVFrame
2404  * structure directly, without encoding it into a packet.
2405  * It is mostly useful for devices and similar special muxers that use raw
2406  * video or PCM data and will not serialize it into a byte stream.
2407  *
2408  * To test whether it is possible to use it with a given muxer and stream,
2409  * use av_write_uncoded_frame_query().
2410  *
2411  * The caller gives up ownership of the frame and must not access it
2412  * afterwards.
2413  *
2414  * @return  >=0 for success, a negative code on error
2415  */
2416 int av_interleaved_write_uncoded_frame(AVFormatContext *s, int stream_index,
2417                                        AVFrame *frame);
2418 
2419 /**
2420  * Test whether a muxer supports uncoded frame.
2421  *
2422  * @return  >=0 if an uncoded frame can be written to that muxer and stream,
2423  *          <0 if not
2424  */
2425 int av_write_uncoded_frame_query(AVFormatContext *s, int stream_index);
2426 
2427 /**
2428  * Write the stream trailer to an output media file and free the
2429  * file private data.
2430  *
2431  * May only be called after a successful call to avformat_write_header.
2432  *
2433  * @param s media file handle
2434  * @return 0 if OK, AVERROR_xxx on error
2435  */
2436 int av_write_trailer(AVFormatContext *s);
2437 
2438 /**
2439  * Return the output format in the list of registered output formats
2440  * which best matches the provided parameters, or return NULL if
2441  * there is no match.
2442  *
2443  * @param short_name if non-NULL checks if short_name matches with the
2444  * names of the registered formats
2445  * @param filename if non-NULL checks if filename terminates with the
2446  * extensions of the registered formats
2447  * @param mime_type if non-NULL checks if mime_type matches with the
2448  * MIME type of the registered formats
2449  */
2450 AVOutputFormat *av_guess_format(const char *short_name,
2451                                 const char *filename,
2452                                 const char *mime_type);
2453 
2454 /**
2455  * Guess the codec ID based upon muxer and filename.
2456  */
2457  AVCodecID av_guess_codec(AVOutputFormat *fmt, const char *short_name,
2458                             const char *filename, const char *mime_type,
2459                             AVMediaType type);
2460 
2461 /**
2462  * Get timing information for the data currently output.
2463  * The exact meaning of "currently output" depends on the format.
2464  * It is mostly relevant for devices that have an internal buffer and/or
2465  * work in real time.
2466  * @param s          media file handle
2467  * @param stream     stream in the media file
2468  * @param[out] dts   DTS of the last packet output for the stream, in stream
2469  *                   time_base units
2470  * @param[out] wall  absolute time when that packet whas output,
2471  *                   in microsecond
2472  * @return  0 if OK, AVERROR(ENOSYS) if the format does not support it
2473  * Note: some formats or devices may not allow to measure dts and wall
2474  * atomically.
2475  */
2476 int av_get_output_timestamp(AVFormatContext *s, int stream,
2477                             int64_t *dts, int64_t *wall);
2478 
2479 
2480 /**
2481  * @}
2482  */
2483 
2484 
2485 /**
2486  * @defgroup lavf_misc Utility functions
2487  * @ingroup libavf
2488  * @{
2489  *
2490  * Miscellaneous utility functions related to both muxing and demuxing
2491  * (or neither).
2492  */
2493 
2494 /**
2495  * Send a nice hexadecimal dump of a buffer to the specified file stream.
2496  *
2497  * @param f The file stream pointer where the dump should be sent to.
2498  * @param buf buffer
2499  * @param size buffer size
2500  *
2501  * @see av_hex_dump_log, av_pkt_dump2, av_pkt_dump_log2
2502  */
2503 void av_hex_dump(FILE *f, const uint8_t *buf, int size);
2504 
2505 /**
2506  * Send a nice hexadecimal dump of a buffer to the log.
2507  *
2508  * @param avcl A pointer to an arbitrary struct of which the first field is a
2509  * pointer to an AVClass struct.
2510  * @param level The importance level of the message, lower values signifying
2511  * higher importance.
2512  * @param buf buffer
2513  * @param size buffer size
2514  *
2515  * @see av_hex_dump, av_pkt_dump2, av_pkt_dump_log2
2516  */
2517 void av_hex_dump_log(void *avcl, int level, const uint8_t *buf, int size);
2518 
2519 /**
2520  * Send a nice dump of a packet to the specified file stream.
2521  *
2522  * @param f The file stream pointer where the dump should be sent to.
2523  * @param pkt packet to dump
2524  * @param dump_payload True if the payload must be displayed, too.
2525  * @param st AVStream that the packet belongs to
2526  */
2527 void av_pkt_dump2(FILE *f, AVPacket *pkt, int dump_payload, AVStream *st);
2528 
2529 
2530 /**
2531  * Send a nice dump of a packet to the log.
2532  *
2533  * @param avcl A pointer to an arbitrary struct of which the first field is a
2534  * pointer to an AVClass struct.
2535  * @param level The importance level of the message, lower values signifying
2536  * higher importance.
2537  * @param pkt packet to dump
2538  * @param dump_payload True if the payload must be displayed, too.
2539  * @param st AVStream that the packet belongs to
2540  */
2541 void av_pkt_dump_log2(void *avcl, int level, AVPacket *pkt, int dump_payload,
2542                       AVStream *st);
2543 
2544 /**
2545  * Get the AVCodecID for the given codec tag tag.
2546  * If no codec id is found returns AV_CODEC_ID_NONE.
2547  *
2548  * @param tags list of supported codec_id-codec_tag pairs, as stored
2549  * in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
2550  * @param tag  codec tag to match to a codec ID
2551  */
2552 AVCodecID av_codec_get_id(const AVCodecTag **tags, uint tag);
2553 
2554 /**
2555  * Get the codec tag for the given codec id id.
2556  * If no codec tag is found returns 0.
2557  *
2558  * @param tags list of supported codec_id-codec_tag pairs, as stored
2559  * in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
2560  * @param id   codec ID to match to a codec tag
2561  */
2562 uint av_codec_get_tag(const AVCodecTag *  *tags, AVCodecID id);
2563 
2564 /**
2565  * Get the codec tag for the given codec id.
2566  *
2567  * @param tags list of supported codec_id - codec_tag pairs, as stored
2568  * in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
2569  * @param id codec id that should be searched for in the list
2570  * @param tag A pointer to the found tag
2571  * @return 0 if id was not found in tags, > 0 if it was found
2572  */
2573 int av_codec_get_tag2(const AVCodecTag **tags, AVCodecID id,
2574                       uint *tag);
2575 
2576 int av_find_default_stream_index(AVFormatContext *s);
2577 
2578 /**
2579  * Get the index for a specific timestamp.
2580  *
2581  * @param st        stream that the timestamp belongs to
2582  * @param timestamp timestamp to retrieve the index for
2583  * @param flags if AVSEEK_FLAG_BACKWARD then the returned index will correspond
2584  *                 to the timestamp which is <= the requested one, if backward
2585  *                 is 0, then it will be >=
2586  *              if AVSEEK_FLAG_ANY seek to any frame, only keyframes otherwise
2587  * @return < 0 if no such timestamp could be found
2588  */
2589 int av_index_search_timestamp(AVStream *st, int64_t timestamp, int flags);
2590 
2591 /**
2592  * Add an index entry into a sorted list. Update the entry if the list
2593  * already contains it.
2594  *
2595  * @param timestamp timestamp in the time base of the given stream
2596  */
2597 int av_add_index_entry(AVStream *st, int64_t pos, int64_t timestamp,
2598                        int size, int distance, int flags);
2599 
2600 
2601 /**
2602  * Split a URL string into components.
2603  *
2604  * The pointers to buffers for storing individual components may be null,
2605  * in order to ignore that component. Buffers for components not found are
2606  * set to empty strings. If the port is not found, it is set to a negative
2607  * value.
2608  *
2609  * @param proto the buffer for the protocol
2610  * @param proto_size the size of the proto buffer
2611  * @param authorization the buffer for the authorization
2612  * @param authorization_size the size of the authorization buffer
2613  * @param hostname the buffer for the host name
2614  * @param hostname_size the size of the hostname buffer
2615  * @param port_ptr a pointer to store the port number in
2616  * @param path the buffer for the path
2617  * @param path_size the size of the path buffer
2618  * @param url the URL to split
2619  */
2620 void av_url_split(char *proto,         int proto_size,
2621                   char *authorization, int authorization_size,
2622                   char *hostname,      int hostname_size,
2623                   int *port_ptr,
2624                   char *path,          int path_size,
2625                   const char *url);
2626 
2627 
2628 /**
2629  * Print detailed information about the input or output format, such as
2630  * duration, bitrate, streams, container, programs, metadata, side data,
2631  * codec and time base.
2632  *
2633  * @param ic        the context to analyze
2634  * @param index     index of the stream to dump information about
2635  * @param url       the URL to print, such as source or destination file
2636  * @param is_output Select whether the specified context is an input(0) or output(1)
2637  */
2638 void av_dump_format(AVFormatContext *ic,
2639                     int index,
2640                     const char *url,
2641                     int is_output);
2642 
2643 /**
2644  * Return in 'buf' the path with '%d' replaced by a number.
2645  *
2646  * Also handles the '%0nd' format where 'n' is the total number
2647  * of digits and '%%'.
2648  *
2649  * @param buf destination buffer
2650  * @param buf_size destination buffer size
2651  * @param path numbered sequence string
2652  * @param number frame number
2653  * @return 0 if OK, -1 on format error
2654  */
2655 int av_get_frame_filename(char *buf, int buf_size,
2656                           const char *path, int number);
2657 
2658 /**
2659  * Check whether filename actually is a numbered sequence generator.
2660  *
2661  * @param filename possible numbered sequence string
2662  * @return 1 if a valid numbered sequence string, 0 otherwise
2663  */
2664 int av_filename_number_test(const char *filename);
2665 
2666 /**
2667  * Generate an SDP for an RTP session.
2668  *
2669  * Note, this overwrites the id values of AVStreams in the muxer contexts
2670  * for getting unique dynamic payload types.
2671  *
2672  * @param ac array of AVFormatContexts describing the RTP streams. If the
2673  *           array is composed by only one context, such context can contain
2674  *           multiple AVStreams (one AVStream per RTP stream). Otherwise,
2675  *           all the contexts in the array (an AVCodecContext per RTP stream)
2676  *           must contain only one AVStream.
2677  * @param n_files number of AVCodecContexts contained in ac
2678  * @param buf buffer where the SDP will be stored (must be allocated by
2679  *            the caller)
2680  * @param size the size of the buffer
2681  * @return 0 if OK, AVERROR_xxx on error
2682  */
2683 int av_sdp_create(AVFormatContext *[]ac, int n_files, char *buf, int size);
2684 
2685 /**
2686  * Return a positive value if the given filename has one of the given
2687  * extensions, 0 otherwise.
2688  *
2689  * @param filename   file name to check against the given extensions
2690  * @param extensions a comma-separated list of filename extensions
2691  */
2692 int av_match_ext(const char *filename, const char *extensions);
2693 
2694 /**
2695  * Test if the given container can store a codec.
2696  *
2697  * @param ofmt           container to check for compatibility
2698  * @param codec_id       codec to potentially store in container
2699  * @param std_compliance standards compliance level, one of FF_COMPLIANCE_*
2700  *
2701  * @return 1 if codec with ID codec_id can be stored in ofmt, 0 if it cannot.
2702  *         A negative number if this information is not available.
2703  */
2704 int avformat_query_codec(AVOutputFormat *ofmt, AVCodecID codec_id, 
2705                          int std_compliance);
2706 
2707 /**
2708  * @defgroup riff_fourcc RIFF FourCCs
2709  * @{
2710  * Get the tables mapping RIFF FourCCs to libavcodec AVCodecIDs. The tables are
2711  * meant to be passed to av_codec_get_id()/av_codec_get_tag() as in the
2712  * following code:
2713  * @code
2714  * uint32_t tag = MKTAG('H', '2', '6', '4');
2715  * const struct AVCodecTag *table[] = { avformat_get_riff_video_tags(), 0 };
2716  * enum AVCodecID id = av_codec_get_id(table, tag);
2717  * @endcode
2718  */
2719 /**
2720  * @return the table mapping RIFF FourCCs for video to libavcodec AVCodecID.
2721  */
2722 AVCodecTag *avformat_get_riff_video_tags();
2723 /**
2724  * @return the table mapping RIFF FourCCs for audio to AVCodecID.
2725  */
2726 AVCodecTag *avformat_get_riff_audio_tags();
2727 /**
2728  * @return the table mapping MOV FourCCs for video to libavcodec AVCodecID.
2729  */
2730 AVCodecTag *avformat_get_mov_video_tags();
2731 /**
2732  * @return the table mapping MOV FourCCs for audio to AVCodecID.
2733  */
2734 AVCodecTag *avformat_get_mov_audio_tags();
2735 
2736 /**
2737  * @}
2738  */
2739 
2740 /**
2741  * Guess the sample aspect ratio of a frame, based on both the stream and the
2742  * frame aspect ratio.
2743  *
2744  * Since the frame aspect ratio is set by the codec but the stream aspect ratio
2745  * is set by the demuxer, these two may not be equal. This function tries to
2746  * return the value that you should use if you would like to display the frame.
2747  *
2748  * Basic logic is to use the stream aspect ratio if it is set to something sane
2749  * otherwise use the frame aspect ratio. This way a container setting, which is
2750  * usually easy to modify can override the coded value in the frames.
2751  *
2752  * @param format the format context which the stream is part of
2753  * @param stream the stream which the frame is part of
2754  * @param frame the frame with the aspect ratio to be determined
2755  * @return the guessed (valid) sample_aspect_ratio, 0/1 if no idea
2756  */
2757 AVRational av_guess_sample_aspect_ratio(AVFormatContext *format, AVStream *stream, AVFrame *frame);
2758 
2759 /**
2760  * Guess the frame rate, based on both the container and codec information.
2761  *
2762  * @param ctx the format context which the stream is part of
2763  * @param stream the stream which the frame is part of
2764  * @param frame the frame for which the frame rate should be determined, may be NULL
2765  * @return the guessed (valid) frame rate, 0/1 if no idea
2766  */
2767 AVRational av_guess_frame_rate(AVFormatContext *ctx, AVStream *stream, AVFrame *frame);
2768 
2769 /**
2770  * Check if the stream st contained in s is matched by the stream specifier
2771  * spec.
2772  *
2773  * See the "stream specifiers" chapter in the documentation for the syntax
2774  * of spec.
2775  *
2776  * @return  >0 if st is matched by spec;
2777  *          0  if st is not matched by spec;
2778  *          AVERROR code if spec is invalid
2779  *
2780  * @note  A stream specifier can match several streams in the format.
2781  */
2782 int avformat_match_stream_specifier(AVFormatContext *s, AVStream *st,
2783                                     const char *spec);
2784 
2785 void avformat_queue_attached_pictures(AVFormatContext *s);
2786 
2787 /**
2788  * Apply a list of bitstream filters to a packet.
2789  *
2790  * @param codec AVCodecContext, usually from an AVStream
2791  * @param pkt the packet to apply filters to
2792  * @param bsfc a NULL-terminated list of filters to apply
2793  * @return  >=0 on success;
2794  *          AVERROR code on failure
2795  */
2796 int av_apply_bitstream_filters(AVCodecContext *codec, AVPacket *pkt,
2797                                AVBitStreamFilterContext *bsfc);
2798 
2799 /**
2800  * @}
2801  */
2802 
2803 //#endif /* AVFORMAT_AVFORMAT_H */
2804 
2805 
2806 // #defines made inline in structs or enums
2807 enum MAX_STD_TIMEBASES = (60*12+6);
2808 enum AVSTREAM_EVENT_FLAG_METADATA_UPDATED = 0x0001;
2809 enum MAX_PROBE_PACKETS = 2500;
2810 enum RAW_PACKET_BUFFER_SIZE = 2500_000;
2811 enum AVFMT_EVENT_FLAG_METADATA_UPDATED = 0x0001; ///< The call resulted in updated metadata.
2812 enum FF_FDEBUG_TS  =     0x0001;
2813 
2814 enum AVFMT_FLAG_GENPTS   =   0x0001; ///< Generate missing pts even if it requires parsing future frames.
2815 enum AVFMT_FLAG_IGNIDX   =   0x0002; ///< Ignore index.
2816 enum AVFMT_FLAG_NONBLOCK =   0x0004; ///< Do not block when reading packets from input.
2817 enum AVFMT_FLAG_IGNDTS   =   0x0008; ///< Ignore DTS on frames that contain both DTS & PTS
2818 enum AVFMT_FLAG_NOFILLIN =   0x0010; ///< Do not infer any values from other values, just return what is stored in the container
2819 enum AVFMT_FLAG_NOPARSE  =   0x0020; ///< Do not use AVParsers, you also must set AVFMT_FLAG_NOFILLIN as the fillin code works on frames and no parsing -> no frames. Also seeking to frames can not work if parsing to find frame boundaries has been disabled
2820 enum AVFMT_FLAG_NOBUFFER =   0x0040; ///< Do not buffer frames when possible
2821 enum AVFMT_FLAG_CUSTOM_IO =  0x0080; ///< The caller has supplied a custom AVIOContext, don't avio_close() it.
2822 enum AVFMT_FLAG_DISCARD_CORRUPT= 0x0100; ///< Discard frames marked corrupted
2823 enum AVFMT_FLAG_FLUSH_PACKETS =  0x0200; ///< Flush the AVIOContext every packet.
2824 /**
2825  * When muxing, try to avoid writing any random/volatile data to the output.
2826  * This includes any random IDs, real-time timestamps/dates, muxer version, etc.
2827  *
2828  * This flag is mainly intended for testing.
2829  */
2830 enum AVFMT_FLAG_BITEXACT  =  0x0400;
2831 enum AVFMT_FLAG_MP4A_LATM =  0x8000; ///< Enable RTP MP4A-LATM payload
2832 enum AVFMT_FLAG_SORT_DTS  = 0x10000; ///< try to interleave outputted packets by dts (using this flag can slow demuxing down)
2833 enum AVFMT_FLAG_PRIV_OPT  = 0x20000; ///< Enable use of private options by delaying codec open (this could be made default once all code is converted)
2834 enum AVFMT_FLAG_KEEP_SIDE_DATA=0x40000; ///< Don't merge side data but keep it separate.
2835 
2836 enum MAX_REORDER_DELAY=16;
2837 
2838 enum AVINDEX_KEYFRAME = 0x0001;
2839 
2840 enum AVFMT_AVOID_NEG_TS_AUTO              = -1; ///< Enabled when required by target format
2841 enum AVFMT_AVOID_NEG_TS_MAKE_NON_NEGATIVE = 1; ///< Shift timestamps so they are non negative
2842 enum AVFMT_AVOID_NEG_TS_MAKE_ZERO         = 2; ///< Shift timestamps so that they start at 0